CERTIFICATION 2
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or special interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my personal stories, and some marketing I’m a capitalist).
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback, what say you?
So what is the ACO?
It is the Aircraft Certification Office and is RESPONSIBLE for:
- Design approval and certificate management
- US production approvals
- Engineering and analysis questions
- Investigating and reporting aircraft accidents, incidents, and service difficulties
- Designated Engineering Representatives (DER) oversight
or commonly put they are the FAA engineers. Behind them are more engineers writing, coordinating and editing regulations, testing, researching, etc. But ACOs rely extensively on DERs and commonly delegate FSDO and MIDO type issues to them.
I was once visiting Larry at an ACO when it so happened a FSDO inspector from Seattle called questioning whether or not I was a DER. Back in the day there was no handy and accurate directory on the internet so I thought nothing of the question. Larry went ballistic shouting back at the FSDO inspector about how dare question a DER’s legitimacy. Larry cooled down and acknowledged he may have overreacted but he hadn’t had his morning office coffee yet. There are touchy subjects out there people and it isn’t spell check. FSDO doesn’t report to the ACO and the ACO doesn’t report to FSDO. And the Navy doesn’t report to the Army and the Army doesn’t report to the Navy. (But both of them report to the Air Force)
Seriously, they should work together and they all report to the President as does the FAA.
FAA chain of command:
Between FSDO / MIDO and the ACO, there isn’t one. They are supposed to work together within their defined roles and responsibility but as in all good marriages there are differences of opinion (and personalities.) The ACO can trump FSDO the same as a MRB engineer trumps an inspector on the factory floor. But FSDO / inspector can trump the ACO/ engineer depending on the function. Engineering wrote the book so their interpretation wins but FSDO controls the process of approval. A good engineer listens because dare I say it, “the engineer might not have been as clear as he could have been.” “Trust me, I’m an engineer.” Okay stop laughing, we are human even if we don’t show it. We really do laugh quite a bit but usually away from mechanics, inspectors, accountants, managers, and anyone else not an engineer. You don’t think we know when we screw you? And we don’t actually do it, God or nature does it. Engineers have limitations and I wish some engineers would acknowledge it. If we need 2 plus 2 then we will say 4, not what someone else wants us to say even if intimidated.
I take great pride in helping bankrupt three airlines for several good deeds. Remember Peoples Express, two days before redelivery I was able to take a 747 wheel well left hand frame and by cutting it into three separate pieces and splicing them back together, installed it on the right hand side making delivery. Peoples Express didn’t have the cash to take redelivery. Oops, Chapter 11.
I remind you, when I say we or I spliced, installed, made, etc. it means we or I wrote and approved the engineering technical data. The mechanics do the hands on work.
But I take great pride in making scheduled delivery on budget with an acceptable level of quality aircraft repair or alteration that complies with all the requirements. That may sound impossible but if you get a DER’s bill, you will understand it is not impossible just expensive. Seriously a DER works in the world of deviation from the norm.
Repair DERs are the masters of deviation assuring a safe and certified repair. Most A&Ps don’t have a clue what a good engineer can do with structure. I arrived at a modification center and one of my first problems was a vertically cracked fore and aft running L angle along the exterior of the vertical stabilizer. I told them to cut it through into two pieces, blend and smooth, and paint the ends. What chaos broke out after releasing that data. Cutting a structural part into two separate pieces and NOT splicing them back together seem odd to you? Well, it was done after it was explained to the shop by another engineer. It is what we do and we take over where the manuals stop.
CALLAHAN AIRCRAFT SERVICES CURRENT PROJECTS:
CONVAIR 440 AIRBORNE PLATFORM ANALYSIS & APPROVAL
SUPER CONSTELLATION REBUILD REPAIRS APPROVAL
402B UPPER WING WALK REINFORCEMENT REPAIR DESIGN, ANALYSIS & APPROVAL
402C ENGINE MOUNT SHIM REPAIR STC / PMA
E170 & E190 SLAT TOOL JIGS AND CHECK FIXTURES DESIGN, ANALYSIS & APPROVAL
KING AIR “EYEBROW WINDOW” STC / PMA
KING AIR WING ROOT SPAR CAP CRACK AD 89-25-10 AMOC REPAIR DESIGN, ANALYSIS & APPROVAL
KING AIR UPPER AND LOWER EXTERNAL AVIONIC PLATFORMS STC / PMA
ALL COMPOSITE CARGO CONTAINERS STC / PMA
MISCELLANEOUS REPAIRS DESIGN, ANALYSIS & APPROVAL
Next week, “Company versus Consultant DERs” (not a battle but the differences) and the means of approving data. And we haven’t forgotten shimming and by request identifying a shear joint.
Y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving a few minutes of free advice to other aviation professionals.
O x y m o r o n s
AIRLINE SCHEDULES
Words of Wisdom and Warning
“Every step we take towards making the State our Caretaker of our lives, by that much we move toward making the State our Master.”
Dwight D. Eisenhower
Aged to perfection
Growing older we learn miracles are great, but they are so darn unpredictable.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
CERTIFICATION 1
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or special interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my personal stories, and some marketing I’m a capitalist).
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback, what say you?
CERTIFICATION from a DERs point of view by request.
What is a DER?
A DER is a Delegated Engineering Representative of the Federal Aviation Administration. “Designation of a private person as a DER is a privilege granted by the Administrator. It is not the right of every qualified applicant to receive a DER designation.”
“The DER is the connecting link in the engineering team between the FAA and the repair work in the hangar. He does not work for the FAA, but is a member of the Super Star engineering team, yet by virtue of his license as an extended arm of the FAA, he has the authority to make decisions and approve engineering work. “My signature at the bottom of a document carries the same weight as an official FAA stamp,” he says. In this connection DERs are subject to stringent checks on the part of the FAA, they have to submit their signed documents to the assigned FAA specialist supervision office for examination and every year they have to demonstrate their competence in an FAA check. “But we can also approach our FAA contacts on critical issues and obtain advice,” he explains. “In the American engineering world, there are just two industries that are controlled and regulated to this extent – aviation and the nuclear industry – and for good reason!”" Lufthansa Technik
What is an Engineer?
We need to explain what an engineer is in the good ol US of A aircraft industry. And this is a touchy subject when thin skinned junior engineers take offense. An engineer does not have to have a college degree. The Roman Empire engineers designed and built many roads without any college degree.
The Egyptians built the first computer using binary code. It was an irrigation system with go and no-go gates providing water to the exact field intended. I think a lot of farmers are good engineers and a designer does not need to be an engineer.
My older brother still thinks I drive a train but really I drive a tractor.
Engineers design, analyze, test, research, study, and sometimes even do drafting. Most aircraft engineers are Designers but most Structural DERs have been Stress Analyst and usually have at least a bachelors degree in engineering. A Stress Analyst belongs to a Staff or specialist group similar to aerodynamics, thermodynamics, or loads groups. A Stress Analyst crunches the numbers to substantiate the structural strength of the design. The following poster is not a joke, it’s true and these groups get passionate about the importance of their group. They all think they are the most important therefore the actual product is a compromise. Lately the manufacturing engineer has been brought into the act so more committee action and further compromise. So get rid of the idea that the shear tie, stringer is optimally designed for strength. There are areas of primary structure that are literally over-designed by a magnitude of 5 or more times. The secret is to know where is over-design is.
Back to DER: “A DER may approve or recommend approval of engineering technical data within the limits of their authority by means of FAA Form 8110-3, Statement of Compliance with the Federal Aviation Regulations.” Or as commonly put he is delegated the authority to approve data. Talk about double talk “engineering technical data” when is engineering data not technical? He only cares about aircraft safety and factually justifying it. He doesn’t care about producibility or maintenance costs or schedule because that is not his FAA charter.
A DER is not an inspector or mechanic; he only approves technical data.
What is engineering technical data?
A&P mechanics see it as drawings, manuals, bulletins, or Technical Orders. Airworthiness Directives, Test and Stress Reports, specifications, processes, procedures, etc are engineering technical data. Engineering writes the manuals that A&P mechanics follow be it from any source as long as it is approved by the FAA usually by an OEM or a consultant DER.
There are derivatives that others write based on approved engineering technical data that may be translated into work orders or jobs. Engineering and therefore DERs are moving (being nudged by the FAA) into this business too. I guess the FAA has lost faith in the translators? Remember translators have no authority so be careful using their data. An airline may have a FAA approved process allowing qualified personnel to “translate ” approved data and therefore following the planning is acceptable because it is following FAA approved data via an FAA approved process.
14 CFR § 183.29 defines the privilege for appointments in the following technical fields:
(1) Structural Engineering
(2) Powerplant Engineering
(3) Systems and Equipment Engineering
(4) Radio Engineering
(5) Engine Engineering
(6) Propeller Engineering
(7) Flight Analyst
(8) Flight Test Pilot
(9) Acoustical Engineering.
to list some and even these delegations can be limited within these fields. This is why you may need more than one DER. An example may be an antennae installation through a pressurized skin. You would need DERs delegated with Structure Design and Damage Tolerance, Systems and Equipment Electrical and maybe an Acoustical DER.
“A DER offers technical expertise with state-of-the-art knowledge. An FAA specialist understands the framework of critical regulations that allow technology to be applied.”
DER Categories.
a. Company DER.
An ACO may appoint an individual to act as a company DER for his employer. A company DER may only approve, or recommend approval of technical data for the company. If a company DER is assigned to work in a consortium, business arrangement (such as using other company’s DERs), partnership or licensing agreement, the DER’s managing office will define the limits of the DER’s authority.
b. Consultant DER.
An ACO may appoint an individual to act as an independent (self-employed) consultant DER to approve, or recommend approval of technical data for a client. This DER usually has no geographical boundary or aircraft limitation.
DERs are only required for Major Repairs and the A&P mechanic makes the decision whether or not the repair is a Major Repair. Unlike engineers, DERs are a source for approved data and don’t answer to the A&P mechanic nor FSDO or MIDO. A DER answers to the FAA ACO.
An analogy would be the DER is the surgeon, the engineer is the doctor, the A&P mechanic is the Registered Nurse, assemblers are the CNAs, etc.
I know a DER that made one phone call and instantly had two mechanics dismissed. Another time FSDO inspectors were fired. You see, a DER should know when a FSDO inspector is outside FSDO’s charter and by going through his congressman FSDO addressed the issue. Don’t think DERs do that for a living, FSDO is usually just fine but there always a few poor apples in the barrel. Except for DERS, we are perfect, just ask us.
So what is the ACO? is for next week and we will get to SHIMMING soon
CALLAHAN AIRCRAFT SERVICES, LLC CURRENT PROJECTS:
CONVAIR 440 AIRBORNE PLATFORM ANALYSIS & APPROVAL
SUPER CONSTELLATION REBUILD REPAIRS APPROVAL
GULFSTREAM III AIRBORNE PLATFORM ANALYSIS & APPROVAL
402B UPPER WING WALK REINFORCEMENT REPAIR DESIGN, ANALYSIS & APPROVAL
402C ENGINE MOUNT SHIM REPAIR STC / PMA
E170 & E190 SLAT TOOL JIGS AND CHECK FIXTURES DESIGN, ANALYSIS & APPROVAL
KING AIR “EYEBROW WINDOW” STC / PMA
KING AIR WING ROOT SPAR CAP CRACK AD 89-25-10 AMOC REPAIR DESIGN, ANALYSIS & APPROVAL
KING AIR UPPER AND LOWER EXTERNAL AVIONIC PLATFORMS STC / PMA
ALL COMPOSITE CARGO CONTAINERS STC / PMA
MISCELLANEOUS REPAIRS DESIGN, ANALYSIS & APPROVAL
O x y m o r o n s
BALANCED FEDERAL BUDGET
Words of Wisdom and Warning
“If a republican government fails to secure public prosperity and happiness, it must be because the citizens neglect the divine commands, and elect bad men to make and administer the laws.”
Noah Webster
Aged to perfection
As we grow older and wiser, we talk less and say more.
But y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving free advice to other aviation professionals.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
RULES OF THUMB AND OTHER MYTHS 6
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or subject interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my personal stories, and some marketing I’m a capitalist).
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback, what say you?
“1.5 e/d is okay” is NOT a good rule of thumb
Working the B757 start up on unit three (I think), we had a manufacturing boo boo. The shop installed the skin rivets all around the emergency exit door cutout with 2.0 e/D. Isn’t that nice but when that barrel section went in for final company or FAA inspection it failed. Why? Because the drawing required 2.5 e/D edge margin.
We figured the skin cutout’s corners lost one third of their life. This means the probability of skin cracks was high after two thirds (20 years) of the B757 design life of 30 years. The Liaison and Stress engineers from both the vendor and Boeing agreed it was unacceptable. But not manufacturing who complained through the Boeing Chief of Design, Jim to the DER, Pete. They agreed it was acceptable and I was informed to “buy it off.” Little ol me, the peon sole On-site Liaison Engineer to the vendor was indirectly told to accept the damage as is.
Passionately I called the Boeing Chief of Design to tell him what for and heck no. He wasn’t known to be real nice to subordinates (remember the Peter Principle) but he was nice to me. Lucky for me I took a Boeing fatigue class (that my Lead informed me was a dumb thing to do) because Jim walked me through their decision process by asking me Boeing technical fatigue and historical maintenance issue questions. We had NO data on this never before completely fatigue designed aircraft! (You CHS engineers working for Tony pay attention) We were using Boeing’s DFR process for design and analysis for the first time. I answered his questions and he summed it by asking me if a crack IF it occurred on THIS aircraft would go UNDETECTED prior to a catastrophic failure (crash and burn).
The answer was “no.”
“And who is taking responsibility for it?”
“Rockwell,” the vendor I replied.
“And who would be paying for the repair?”
“Rockwell,” I replied.
He was willing to accept a low probability of a hit to Boeing’s reputation so I concurred on the acceptance on Rockwell’s paperwork.
The section rolled out, shipped, and received by Boeing in Renton just as I returned from my assignment. Boeing arrogance would not allow them to accept Rockwell acceptance so they wrote Boeing paperwork so Boeing accepted it. I was the turkey to approve the acceptance but this time the DER consigned. So much for the vendor taking responsibility. And a few years later Boeing bought that plant from Rockwell and therefore accepted the repair costs if any.
The point to that story is Boeing Commercial did use airplanes to make money not money to make airplanes like they do now.
A short comment about composite’s end or edge margin requirements. 2.5 e/d is the usual EM requirement but 3.0 e/d isn’t abnormal for graphite or fiberglass composite structure compared to most metals. I don’t remember the requirements for plywood (used on C-130) or wood laminates. Yes, they are composites too making the Wright “Flyer” the first all composite aircraft. Beech’s Chief Engineer Wells book on structural guidelines includes good data for wood and resins and I would go there first, maybe the DC-3 SRM or AN5 Handbook (Army/Navy predecessor to MIL-HDBK-5) second.
DERs are only required for Major Repairs and the A&P mechanic makes that decision whether or not the repair is a Major Repair. Unlike engineers, DERs are a source for approved data and don’t answer to the A&P mechanic nor FSDO or MIDO. A DER answers to the FAA ACO.
But y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving free advice and aviation professionals.
CALLAHAN AIRCRAFT SERVICES CURRENT PROJECTS:
Next week’s topic will be “what is a DER” and coming soon topics will include identifying a shear joint and why some engineers or ARs don’t explain requirements making one feel small. AND shimming
O x y m o r o n s
Click the ‘Start’ button to Shut Down the computer.
Words of Wisdom and Warning
“It is the duty of the patriot to protect his country from its government.”
Thomas Paine
Aged to perfection
Peace is when time doesn’t matter as it passes by.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
RULES OF THUMB AND OTHER MYTHS 5
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my stories, and some marketing.
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback what say you?
“1.5 e/d is okay” is NOT a good rule of thumb
Let’s look at allowables for bearing in 2024-T3 sheet. I pick this material because numerous aircraft skins are made from this material.
Without any other differences the allowable for bearing in metal sheets drops the closer to the edge of the part. There is a direct relationship between the allowable and the load carrying capability of the fastener.
Load or force is equal to material thickness times fastener diameter times material ALLOWABLE or = t * d * Fbru
The further away from the end of part the better the allowable or the higher the load the fastener can carry. This is true but there are a couple of things to consider like fastener shear capability or strength and material tear out (just too close to the end of part).
So if drilling a hole with 1.5 e/d versus the design or SRM requirement of 2.0 e/d then in 2024-T3 thin sheet the joint lost 20% of its strength.
99 ksi / 123 ksi – 1 = -20%
A loss of 20% is quite a bit and consider you haven’t done anything else wrong. Oops, you gouged the edge a little so you blend it out. After all it was hardly 5% deep. Really, so now we combine the 20% loss with that specific 5% loss and things are not looking to good but hey, no one notices and my Lead says it’s no big deal.
You decide you want to address it because it isn’t right to ignore it (and you don’t want to jeopardize your A&P license) so what do you do? Sounds bad but in the real world if my boss says its okay then have him sign it off. After all how many rivets has he installed with 1.5 e/d and you never heard of a plane crashing because of it.
Working the B727 production line, I had to address a significant gouge in the main landing “walking” beam that is made from 4330 steel (it may be 4340). Drawing called for shot peening but we used flap peening for repair work. I thought about it and specified SHOT peening and that may be messy considering the plane was already on its gear.
I talked it over with a more senior engineer, Jose. He had four years experience compared to my two. He agreed with me but my Lead, Chuck got involved (shop probably complained.) You see I thought the main landing gear main beam was very important but what did I know. Well, it was just terrible with him calling me a “woose” and giving me his eyes of intimidation. I almost broke but I stuck to me guns and replied, “then you sign it.” He called me and Jose something like cowards and shook his head walking away. But he didn’t change or sign it. The poor shop guys had to place heavy plastic sheet all over the place leaving only the repaired area exposed for shot peening. I think I learned something that day except the next time I tried that I was sent to the doghouse by my Lead, Bob. I guess all Leads are not the same and that is what I learned that day. Funny thing is I don’t use rotor or flap peening anymore for repair work, I just call out a smoother surface finish something I learned while working for that Lead Bob.
Another choice is a DER’s or a trusted engineer’s opinion. It isn’t always possible to get that simple opinion because it may not be simple. Send some pictures of the joint (12″ x 12″) and another one of the area (6′ x 6′) from both sides. Please, don’t send a picture 1″ x 1″ large because we can’t do anything with that data. We need to understand the load path because short end margin only exists parallel to the load otherwise it is short edge margin (a fatigue issue)
But remember a free opinion is usually only worth what it cost. I learned that from my daughter the Attorney. Her Law professor told her that is what she should tell family members when they want her services for free or at a discount.
Did you notice how I mentioned short edge margin and short end margin are different? Short end margin is parallel with the load and short edge margin is perpendicular to the load. But there are more than one load case and sometimes they switch or they are both like in SEM. So if you don’t know the critical load direction, you don’t know it is SEM or SEM.
Let’s return to the equation
Load = t * d * Fbru
If the diameter is increased the fastener load goes up, right? Nope because that dang allowable goes down! But maybe not at the same magnitude. Maybe a 25% diameter increase only drops the allowable 20% then we have an overall increase. Except what about the other failure mode in a shear joint, tension? Yep, we lost cross-sectional area. Si don’t drill holes with 1.5 e/d because it may not be acceptable and if you do call a DER for advice.
So A&P mechanics follow the SRM to the best of your knowledge and authority and don’t rely on hearsay.
Engineers massage the SRM to the utmost supporting the A&P mechanic but remember he is the authority and the final decision maker. You may show it structurally sound but A&P mechanic has the responsibility.
DERs are only required for Major Repairs and the A&P mechanic makes that decision whether or not the repair is a Major Repair. Unlike engineers, DERs are a source for approved data and don’t answer to the A&P mechanic nor FSDO or MIDO. A DER answers to the FAA ACO.
But y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving free advice and aviation professionals.
Next week we will continue with some calculations demonstrating why “1.5 e/d is okay” is NOT a good rule of thumb.
CALLAHAN AIRCRAFT SERVICES IS CURRENTLY WORKING THESE PROJECTS:
O x y m o r o n s
Cheap is more expensive.
Words of Wisdom and Warning
“America will never be destroyed from the outside. If we falter and lose our freedoms, it will be because we destroyed ourselves.”
Abraham Lincoln
Aged to perfection
In spite of the cost of living, it’s still popular.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
RULES OF THUMB AND OTHER MYTHS 4
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or special interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my personal stories, and some marketing I’m a capitalist).
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback, what say you?
“1.5 e/d is okay”
A young liaison engineer at Lockheed—Georgia scrapped a wing shear tie because it had 1.5 e/D EM and he could not justify it by analysis. He dispositioned the paperwork to fabricate a new one the same as but with 2D EM. Well, the shop manager (2nd level) blew a gasket. He complained to the Director of Engineering! “The previous liaison engineer always bought it off.” The Director invited the young Liaison Engineer to his office to explain his actions. The engineer showed him the analysis (he had stress double check it by now) and the Director defended the disposition. What do you think the previous Liaison Engineer felt like. The rest of the story is the young Liaison Engineer was made Lead shortly thereafter. True story.
Here we go with my stowbin story. On the 747 CRAF program we installed new center stow bins and supporting structure. After six units were delivered we heard the story about one of the maiden revenue flight’s mishap. It seems a center stow bin broke loose, fell and hit a passenger. I say it seems because that is what we heard through the grapevine. Nevertheless we had a center stow bin failure. I was assigned to find out why.
Where do I begin? At the beginning when the supporting structure is assembled in the back shop. The fore & aft rails were laid over tables positioned side by side (not end to end) with several feet between them allowing the rails to droop. This is the up and down of the roller coaster. This rail assembly went to the aircraft and was located into position with very expensive tooling. The tooling looked like ladders attached to the pair of center seat tracks. Sounds good but the seat tracks were not designed nor installed level with respect to each other. The tolerance was .25 and at a height of ten feet that meant a side slope of 2.5 inches. That is the side to side of the roller coaster. Now bring on the stow bins with tool jig located six attachment fittings and only one set of attachment holes lined up, the first ones. But have you ever heard of a hammer? After a few hard whacks all went together perfectly (until that passenger got hit.) Well, we placed those table end to end butted up against each other, replaced those “ladders” with a string and nut, and located the stow bins without a hammer. In fact, the crew was amazed how the bolts slid right in at all 6 places (so was I.)
But what has that got to do with 1.5 e/d? I’ll tell you. One of the reasons the stowbin fell was because the 1/4 inch bolts were installed with .38 EM (1.5 e/d) not the – ready – .53 EM or 2.5 e/d requirement! And this was interior structure. There are several places where 2.5 e/d is required on primary structure and others where 1.0 e/d is required. Yes, sometimes we (engineering) want a certain structure to fail to save the joint or aircraft. So if 1.5 is used then the wrong structure may fail. The DC-10 pylon catastrophic failure is an example of that. The forward engine mount was designed to fail first before the aft engine mount. The design failure would have the engine fall down and away under the wing causing some momentary excitement in the cockpit. But the crash was caused by the aft engine mount failure making the engine wrap around the front spar severing the hydraulic lines. The aircraft rolled and plowed into the ground with all board dead. The accident was from poor maintenance practice not following the manual. Yeah but gees it saved time and we all know that is the most important. After all it never failed before.
Never failed before so start shaving the excess off. Remember the JAL B747 that spun gently into the hill killing all but a baby? The Aft Pressure Bulkhead failed. So later on, on the mod line we found nearly every 747 we modified had severe corrosion on those Aft Pressure Bulkhead webs. They were removed and replaced and then one day we were handed a rejection tag concerning short edge margin on the new .032 webs. There were a few holes with less than 1.5 e/d. Funny, it went from less than 1.5 e/d to more than 2.0 e/d. Yeah right. Inspection had been accepting down to 1.5 e/d after that JAL crash! The tag was rewritten addressing all holes even the good ones. You see Engineering needs all the data. Without the good data we would have replaced those webs again. As it were we oversized some and accepted the bad ones. We address the joint not the hole. Inspection inspects each hole, we address the joint. And we measure the thicknesses, spacing, etc. to see the joint actual condition.
So A&P mechanics follow the SRM to the best of your knowledge and authority and don’t rely on hearsay.
Engineers massage the SRM to the utmost supporting the A&P mechanic but remember he is the authority and the final decision maker. You may show it structurally sound but A&P mechanic has the responsibility.
DERs are only required for Major Repairs and the A&P mechanic makes that decision whether or not the repair is a Major Repair. But guys, we do take questions and we are on the same team. Most DERs are comfortable in their role and don’t mind giving free advice. DERs are supposed to be aviation professionals.
Next week we will continue with some calculations demonstrating why “1.5 e/d is okay” is NOT a good rule of thumb.
CALLAHAN AIRCRAFT SERVICES IS CURRENTLY WORKING THESE PROJECTS:
O x y m o r o n s
Why don’t they make the whole airplane out of that black box stuff?
Words of Wisdom and Warning
“The man who reads nothing at all is better educated than the man who reads nothing but newspapers.”
Thomas Jefferson
Aged to perfection
Old enough to know my limit, young enough to exceed it.
Y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving a few minutes of free advice to other aviation professionals.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
RULES OF THUMB AND OTHER MYTHS 3
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or special interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my personal stories, and some marketing I’m a capitalist).
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback, what say you?
“you only need 9 out of ten rivets”
I heard this several times in production and post production. “An engineer once told me you only need 9 out of ten rivets in a skin splice” or “there is an extra 10% thickness”
Really? I can show you where there is 3 times the thickness needed and where there isn’t enough. You see when the aircraft is designed the cost of manufacturing is a significant concern not perfecting the design. And example is when a skin panel needs to be .058 thick would you use .063 thick or .063 and chem mill (EPA!) or machine the skin panel to .058. Another example is when a skin panel needs to be .012 thick would you use .020 thick or .020 and chem mill or machine the skin panel to .012. Considering scrap rate maybe .032 thick would work nicely. And that my friends is why you only need 9 out of 10 rivets if you are in those places. But what if .0796 thickness was needed and .080 was used at your location? Then 10 out of ten is needed! Stick to the SRM but a good engineer can massage that SRM to “increase” the allowable damage. A DER can get even more liberal and even more with a price. The price may be limited life or increased inspections.
Another rule of thumb is 8:1 crippling ratio is acceptable. Well, this seems to hold true. If the height of the free flange is less than 8 times the thickness of the free flange then the flange will not cripple in compression. So what is crippling? Crippling is localized buckling of a part compared to the part buckling, crippling is only worried about the free (not attached or supported) flange(s) buckling. This may be the usual compression failure mode in aircraft design. Ever notice those bulbed angles that don’t attach to anything? That bulb is for crippling critical parts and that means that 10% RULE DOES NOT APPLY TO THE BULB! and the critical load is compression.
That saying that “there is an extra 10% thickness” is bogus. I have approved more than 50% removal total and 100% local removal. You A&P mechanics need to read the SRM of the aircraft you are working on. Older aircraft may not even have a SRM so use AC43.13-1 or -2 but only on non-primary structure. AC43–1 and -2 states not for major repairs. And not all SRMs are approved data so make sure it is before you use it for approved data.
Another rule of thumb is data from the OEM is approved data. No way Jose. OEM data is acceptable data unless it comes with FAA approval like an 8110-3. Boeing or Cessna are not the FAA.
Next week, “1.5 e/d is okay“
CALLAHAN AIRCRAFT SERVICES IS CURRENTLY WORKING THESE PROJECTS:
O x y m o r o n s
I’m from the government, I’m here to help.
Words of Wisdom and Warning
“If ever time should come, when vain and aspiring men shall possess the highest seats in Government, our country will stand in need of its experienced patriots to prevent its ruin.”
Samuel Adams
Aged to Perfection
You have to climb the mountain to appreciate the beauty of the view.
Y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving a few minutes of free advice to other aviation professionals.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
RULES OF THUMB AND OTHER MYTHS 2
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or special interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my personal stories, and some marketing I’m a capitalist).
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback, what say you?
Continuing with my first introduction into American business being McDonald’s where I learned the importance of processes and pro-activeness. Their process took an idiot like me and within hours taught me to cook 36 hamburgers, prep the buns, cook 10 quarter pounders all at the same time and I remember being intimidated by the “old” cooks that were a year younger than me.
The proactive night manager at a particular time stood at the front door night after night then turn to us and softly yell “3 sets.” We would lay 36 burgers down on the grill with no customers in sight. Three minutes later the head lights showed up outside and as the burgers come off the grill people piled into the store. The night manager had called the local movie theater and asked for when the movies would let out. Then he watched as they went to there cars and softly yell “3 sets” That was pro-active management.
While at NWA, Rich and I tried introducing a proactive maintenance. Everything was good except for upper management. They were in that blame and CYA game.
Recently while in Charleston on the 787 the lack of pro active management was one of the worse I’ve ever seen. My manager didn’t even plan for the next hour. He was into that blame and CYA game too. There will be many funny stories from those assignments but back to technical.
So more about wording.
“Engineering always buys it off’” is a phrase I used to hear in production quite a lot because it used to be true. In fact it was called S&FA or what I liked best UAI short for Use As Is. So for us to accept the discrepancy as is was a normal thing. It was drilled into me that Engineering is not inspection nor police. If nothing needs to be done then UAI is the best repair for quality, cost, and schedule. There is no place for emotion in our disposition by placing punitive action in it. The only time we “policed” something was when we saw it concerned safety of flight.
Today UAI is frowned upon and the engineer in the shop is instructed to police and inspect the area he visits. A UAI as thought of as you are not doing your job and you can’t use that term anymore. It must be something like “Structurally and Functionally acceptable because …” but don’t use it too often or your peers may think evil thoughts about you. Today the emphasis is on never being wrong and it is worth repeating “never being wrong” so scrap is now the preferred disposition or find someone else to take responsibility. And if I’m right, why have the needless overhead. Or at least decrease the staff to a level that can just support very expensive parts, many many man hours, or significant schedule impact when a good engineer is really needed. Keeping a full staff costs too much money. I heard it cost $2000 to process a discrepancy through the system but if the part is only worth $600 why ask an engineer to scrap it? Because they are available and why would Quality take responsibility if there is someone else to take it. Post production operations may not even have an engineer on staff but use the OEM or a Consulting DER (like myself.) We are expensive when used but only when used. I consider myself like a plumber or fireman waiting for the call.
I attended a Boeing 787 Engineering repair symposium back in the Spring of 2010 and was amazed at the inexperience and lack of knowledge of their technical staff group (the OEM DERs and Stress). Imagine being two years late on certification and just realizing it might be a good idea to have some data on bad holes in composite structure. What did they think? Every hole would be perfect? And that brings up the “remove and replace” disposition. Call the fireman and he comes to the fire without a hose or any water. He turns to you and says, “remove and replace.” And reminds me when Rockwell Intl Tulsa on the B-1B didn’t order one over-size Hilok pin because they weren’t listed on any drawing. They called the plumber and he didn’t even bring his toolbox. But that was Procurement’s error like the one on the C-5B where they only ordered shear pins (no tension pins) because the were cheaper (but weaker!) Hmm. Plumber didn’t bring the right washers. I personally have gone through quite a few plumbers trying to get my office drain and HVAC installed and then fixed.
I guess I’m a little sarcastic because the 757 was state of the art and “it has never been done before” about fatigue techniques. I remember a “remove and replace” disposition because of a bad hole and lack of data to support a repair. But only once and the B757 made delivery on time.
The other amazing thing was the attitude that every discovery 787 Engineering made was thought to be the first time the world ever knew about it. It was emphasized that accepting damage might be the best way to approach the repair. In other words, UAI was being pushed as a NEW idea. And this is because the ‘required’ repairs were not going as well as advertised. And don’t think the process changed over night, it was taking years. And this is usual on any new project run by technocrats that the don’t know everything and that the troops turn on the dime.
Back in the last century pre-AF-1 arrived in Wichita into the new AF-1 hangar to be jacked up for the modification work. AF-1 hangar is down the tarmac from the 747 mod line where one after another 747s were being overhauled and modified from passenger to freighter which also required jacking the aircraft.
The local Staff Engineers along with Liaison Engineers began the passenger to freighter program coordinating with Seattle’s jacking expert engineer. The responsibility went from Seattle to Staff to Liaison and then to Operations management. The process was streamlined with increased experience on every aircraft. It took minutes to safely jack a 747.
Back to AF-1′s jacking experience where a Design Engineer (a non hands on engineer concentrating on the design) with no jacking experience was put in charge. The shop crew were all new to the 747 model being new hires or from the KC-135 military program. Well, I’m not going to tell you what exactly happened but that Designer was gone and the “experts” from the 747 mod line were brought in to finish the jacking operation and handle the “damage.” And like usual the designer got the credit and Liaison wasn’t even mentioned. Did you know they did the same thing on Unit 2 (there are two AF-1s) and I was brought down again. Sometimes it easy to look good but I knew they were a quite few of us capable of doing what I did.
Do you notice how I float around but it is hard not to tell the whole story straight through. Back to that 787 symposium on maybe we shouldn’t fix what isn’t broke or leave well enough alone (I guess those sayings are new too). The other amazing thing was how it is important that you know what you are fixing. Amazing. In other words, know where you are and what the configuration of the design and damage is. On metal airplanes we like to know what the material, thicknesses, shape, etc. This symposium thought they “discovered” this idea of knowing the material, thicknesses, oops I mean layers, shape, etc. You see they were so quick to repair and assume they were state of the art they didn’t notice there was nothing wrong. That’s not a joke or hype. I mean they had a gouge two layers deep in a 12 layer panel that only required 9 layers. So having 10 good layers is better than 9 good layers last I remember. But geese the computer template said the panel was 10 layers so they thought there were only 8 good layers. But this was a huge announcement at the symposium, “know what the damage is!” I nearly fell over.
This particular repair is called a scarf repair and I was told repeatedly this was a first ever. I replied I did my first one on the Shuttle Atlantis payload doors in 1982 but we called it an overlay ply repair. I showed them the Dash 8 SRMs overlay ply repair from the late 80′s. This ain’t new, its kind of old school. Basically it is the same as fiberglass overlay ply repairs of the 50′s ( I was being born) except one uses new materials. I was very surprised nothing changed not even the step back on each repair ply.
While consulting at NWA a decade ago, I was a novice to airline processes but not to common sense and the aircraft repair. Being from Wichita at the time and working in Detroit, I planned Thanksgiving in Detroit because that Wednesday before is supposedly the busiest day of the year for the airlines. But what did I know about the airlines. So with my family traveling to Detroit, we settled down to dinner. It was quiet then but not that previous evening. I started getting phone calls from all over the planet about damaged NWA aircraft but I was assigned only to Detroit. Long story short, I was the only engineer NWA working that evening with all the NWA engineers leaving early that day. But like I said what did I know about the airlines. The next year the engineers had to be on duty for the holidays.
[But the caveat is they didn't have to be at their desk. So they answered their mobile phone and said. "replace the part." And this time I did hype it up a bit but the point is engineers do have lives and no one can really question them except another engineer.]
Summing this up, nothing is new only different with new people and tools. And because engineering says “remove and replace it” does not mean the part is no good so get a second opinion when cost / schedule justified. Most parts can be saved, it is just a matter of money or time, but those two things shouldn’t be left up to the engineer because it may be easier and quicker for him to save the part than for you to replace a part.
Next week, “you only need 9 out of ten rivets”
CALLAHAN AIRCRAFT SERVICES IS CURRENTLY WORKING THESE PROJECTS:
O x y m o r o n s
Why do we wash bath towels? Aren’t we clean when we use them?
Words of Wisdom and Warning
“I have but one lamp by which my feet are guided, and that is the lamp of experience. I
know of no way of judging the future but by the past.” Patrick Henry
Aged to perfection
The longer we live the more we learn it is not who has the most – it is who makes the most of what he has.
Y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving a few minutes of free advice to other aviation professionals.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
RULES OF THUMB AND OTHER MYTHS 1
Happy New Year and that means a new format. I heard that I got too technical (and dry) so here is the new schedule. Mondays will be the post and it will contain technical, quotes, and stories. The technical will be excerpts from my book, quotes will be from several humor and historical sources, my stories will be from my career, and advertising.
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or special interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my personal stories, and some marketing I’m a capitalist).
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback, what say you?
My first introduction into American business was McDonald’s. Yep, I was a teenager and one night watched as the cash registers were replaced by computers with touch pads. I was told each one cost $50k (1974) So I asked why and was informed they would recover their costs in a month. That is how bad the cashiers were in giving back change and handling the cash drawer. I hadn’t decided to be an engineer at this time but tempted to major in history. The night manager had a degree in History and one of his duties was to count the garbage in the garbage pails. Not the ones out front but the ones behind the counter. I decided to be an engineer what ever that was and keep history as a hobby. But back to why did he count garbage. McDonald’s collected data on waste and this is how they collected it. We cooks were encouraged to throw away beef patties or any food dropped on the floor. Imagine that, the boss telling us to throw out good beef. I did but I don’t remember dropping very many.
For the record McDonald’s enforced the rule about throwing away dirty food and if we weren’t cooking we had to be cleaning (wiping the grill prep area) even if we just finished cleaning. Like I said I was a teenager and thought McDonald’s was weird about cleaning.
I wonder what the other greasy spoon places do?
So a story about section properties using the previous blogs. I was presented a corroded Cessna Twin wing spar joint fitting. I charged $600 for the blend and smooth FAA approval (corrosion was limited to the non-critical end) but the owner balked at the cost and didn’t believe it was right to remove material. After whining about the cost his group of four doctors went for part replacement. The 7075-T6 fitting cost $600 and the labor was $1200. My blend and smooth actually improved the joint by removing the fatigue hard point (fitting was a constant shape – no taper or steps), improved corrosion protection (added enamel and sealant and increased smoothness), and decreased aircraft weight. The shop manager and I laughed at a doctor stressing over $600 so he doubled his cost with decreased quality and waited on the new fitting.
There is a misconception the OEM part is better than a PMI or a repair. Quite the contrary, my repairs usually update the engineering improving the part or joint. Remember, these General Aviation airplanes were manufactured and designed many, many years ago before we knew fatigue well. These airplanes were designed for 8 years not the thirty they are experiencing. If you call the OEM you get a replacement part with the same flaws. But be cautious using any engineer because the new ones have trouble using a slide rule method (the way these airplanes were analyzed)
This “RULES OF THUMB” chapter takes on the assignment of identifying all of the ‘Rules of Thumbs” and explaining their history, justifications and limitations.
Let’s start with wording.
“Never say always or never.” And be careful with the words “entire”, complete”, and “all.”
As a Structural FAA DER, we MUST say our approval is complete or state what is not approved. What a bogus statement but we comply.
An antennae installation requires a structural approval for cabin skin penetration on a pressurized vessel but wouldn’t electrical systems be affected? I’m structures so how do I know what electrical regulations are affected?
Ask the FAA and get the bureaucratic run around. In the good old days, we got straight answers even if we did get yelled at when we did.
CALLAHAN AIRCRAFT SERVICES IS CURRENTLY WORKING THESE PROJECTS:
Another word I like is the word “will.”
Its reported prior to the B747 maiden flight, the Chief Engineer was asked, “so will it fly?”
“Should.”
People got upset because he did not say, “yep.”
An engineer can’t predict the future and we do everything possible to ensure safe flight but things happen. Duh, look at history like the Comet. The Comet program was short lived and crushed the British aerospace industry. But the engineers thought it should have flown safe for a long time.
I bet if you ask an “engineer of today” he will say, “yep.”
Next week, “Engineering always buys it off’
O x y m o r o n s
If love is blind, Why is lingerie so popular?
Words of Wisdom and Warning
“When the resolution of enslaving America was formed in Great Britain, the British Parliament was advised by an artful man, who was governor of Pennsylvania, to disarm the people; that it was the best and most effectual way to enslave them; but that they should not do it openly, but weaken them, and let them sink gradually…I ask, who are the militia? They consist A militia, when properly formed, are in fact the people themselves … and include all men capable of bearing arms.” Richard Henry Lee (founding father)
Aged to perfection
Wrinkles are only bypaths of many smiles
Y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving a few minutes of free advice to other aviation professionals.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
SECTION PROPERTY 11
INTRODUCTION OF AIRCRAFT STRUCTURAL REPAIR TECHNIQUES FOR MECHANICS BY AN ENGINEER. This Blog’s target audience is A&P sheet metal mechanics and new structural engineers. Feel free to comment or ask questions.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or special interest.
Posts will be on Mondays containing technical, quotes, and stories. The technical will be excerpts from my book or by request, quotes will be from several humor and historical sources, my personal stories, and some marketing I’m a capitalist).
I’ve decided to present my new book by way of online classes. Each chapter will be a class segment. Each module will be available online for a fee. This seems to be the future but it does allow me to teach a chapter at a time with no travel costs or hassles. There will be interaction by in class work and email. Access to me will also be available. Need feedback, what say you?
O x y m o r o n s
If you are cross-eyed And have dyslexia, Can you read all right?
Words of Wisdom and Warning
“By removing the Bible from schools we would be wasting so much time and money in punishing criminals and so little pains to prevent crime. Take the Bible out of our schools and there would be an explosion in crime.” Benjamin Rush (founding father)
Aged to perfection
The aging process is alot like grapes, some turn to vinegar but the best turn to wine.
Y’all, DERs do take questions and are on the same team. Most DERs are comfortable in their role and don’t mind giving a few minutes of free advice to other aviation professionals.
Sincerely,
James W. Callahan
General Manager / FAA DER
DER@CALLAHAN.AERO
256-891-3677
P.O. BOX 533
Albertville, AL 35950
SECTION PROPERTY 10
O x y m o r o n s
Christmas – What other time of the year do you sit in front of a dead tree and eat candy out of your socks?
Words of Wisdom and Warning
“To maintain the ascendancy of the Constitution over the lawmaking majority is the great
and essential point on which the success of the [American] system must depend; unless
that ascendancy can be preserved, the necessary consequence must be that the laws will
supersede the Constitution; and, finally, the will of the Executive, by influence of its
patronage, will supersede the laws.” John C. Calhoun
Aged to perfection
Age is a matter of the mind; if you don’t mind, it don’t matter.
Visit our website at www.Callahan.aero or e-mail us at der@callahan.aero for any questions or interest.
Sincerely,
James W. Callahan
General Manager / FAA DER
