Consider this: Is it a major repair/alteration or simple replacement?

Sometimes I feel like I’m in an old “Twilight Zone” episode. And I don’t say that because I see space aliens serving man, or I get the creeps thinking about the cornfield, or even that I hear the voice of Rod Serling in my head … well, maybe sometimes. Every Friday night Mr. Serling did two things: 1) told stories that forced us to suspend our way of thinking for a different point of view; a vision that — no matter how farfetched — we needed to consider and understand its meaning; and, 2) often introduced the journey of disbelief with the words: “submitted for your approval.”

Now the inspector in the cubicle next to mine loves to pose random questions to test my knowledge of regulations or policy; he hasn’t learned yet that I usually don’t know the answer. But sometimes he’ll start a discussion on something that he’s working on that challenges the way I interpret how maintenance is conducted per the regulations. I’ve learned that I should suspend how I know the rules and work on how to reconcile them to questionable circumstances.

Submitted for your approval: A Brand-X Aerowidget (foreign manufacturer) goes off the runway incurring substantial damage; the aircraft is considered a total loss … or is it? Diagnosis: Replace the airframe from the wing root forward; Brand-X’s SWAT team assists the operator. The operator’s name is unimportant, but your mission is: determine if it’s a major repair/alteration or simple replacement … in the Aviation Zone (sorry, couldn’t resist).

From the manufacturer

Now seeing that the airframe sustained “substantial damage,” the answer is obvious: major repair. But the manufacturer’s version in this true story said: No. While reviewing the approved data it’s spelled out this work is not a major repair/alteration; no doublers were used, they were replacing part for part, rivet for rivet; case closed.

The structural strength of the new fuselage was never compromised. The replacement section was off the assembly line, technically the same down to the rivet. All structure is i-dent-i-cal, not even requiring more wiring. So again, is it a major repair/alteration?

According to the FAA

The FAA view on major repair/alteration says: Yes. It responded: the replacement of so much Primary structure and the use of fixtures and lasers to line up the hull are too involved to be just simple component replacements. Where are the 337s?

Meanwhile, the Part 121 operator is in the middle trying to work to the FAA standards while following the manufacturer’s approved data. I’ll bet Orville didn’t see this one coming. Let’s look at 14 CFR Part 1.1 for Major Repair/Alteration:
(In addition to an alteration not listed in aircraft, engine, or propeller specifications)

(1) That, if improperly done, might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) That is not done according to accepted practices or cannot be done by elementary operations.

The NTSB explanation

This is an example of when to read precisely what the regulation says. Considering how much structure was restored, the grey line darkens in favor of a major repair/alteration. With that much aircraft replaced, it can’t be an even swap as Brand-X suggests. But remember what I said about substantial damage? It was the NTSB explanation that drove the decision made by the FAA.

According to 49 CFR 830, the NTSB makes the call on whether the aircraft is involved in an accident; it determined this particular airframe suffered substantial damage (there’s that term again). The NTSB defines substantial damage as: “damage or failure which adversely affects the structural strength, performance, or flight characteristics of the aircraft and which would normally require major repair or replacement of the affected component (singular, not components).” When asked, the manufacturer said that it was repairing a broken aircraft, which in itself eliminated all doubt.

What does it take for return to service?

But what we need to consider: what does a major repair/alteration require? An IA (or in this case, RII) to return the aircraft to service. For A&Ps everywhere, changing a hydraulic pump (component) may not require inspection. To say a 40 percent hull replacement with fixtures and laser symmetry is comparable to a pump change is crossing the line on common sense.

But look further; what does “appreciably affect” mean in the definition above, or “elementary operations” for that matter? They’re not defined by FAA policy or regulation; no doubt they’re pretty ambiguous, I agree. Is appreciably affected something to be measured on a scale of one to 10? If so, does it apply evenly to both a 747 and a Cessna 172? The definition has latitude … a lot of latitude! But in the least, the aircraft will have to be reweighed; one must realize this fact makes it a major repair. That’s before you test fly it for trim checks; another reason for major repair.

And what about elementary operations? Again, this statement is ambiguous, but can be cured with common sense (or a call to your FSDO). It’s been years since A&P school; are they requiring laser sited symmetry equipment for your toolboxes these days? The lessons learned in school or as an apprentice were that if you needed it for your toolbox, these were your elementary tools. I know they never called them that, but did you ever keep a fuselage fixture in your hotdog cart? Tooling, like electron beam welders are for extra-ordinary operations and accomplished with special training.

Industry acronyms

Oh, and if you’ve ever worked Douglas (anything with a DC in front of it), Boeing, and/or Airbus aircraft (I worked all three), you know that acronyms are not shared-and-share-alike. In this case the same can be said about Brand-X; their acronyms conflict with the FAA acronyms and thus their intent. Example: the FAA version of PSE means Primary Structural Element, e.g. keel beam, spar, bulkhead; if you lose it you fall at 9.8 feet per second squared. The Brand-X version of the acronym PSE means Principle Structural Element, e.g. L-1 windscreen, landing gear, etc; the aircraft will not collapse in upon itself.

In the scenario above, when the SWAT team used the acronyms interchangeably they were in conflict … big time, when replacing the aircraft section. They required inspection on PSE parts, their version, not the FAA version. The fact that no 337s were employed means the repair was not up to the standards agreed upon between Brand-X and the FAA.

Learning from mistakes

So why is this even an issue? Because the FAA in the place of government overseer finds that industry is learning from their mistakes (and ours); regulations written years ago, their meaning can be changed from the original intent of the rule. Fortunately the repair never made it to flight before the question was raised. But we’re looking out for you guys and gals turning wrenches because it’s the ones on the front lines that get caught between the rock and another hard surface. “Question with boldness,” Thomas Jefferson said, and that is your place to do so. Seeing issues like this demonstrate that even approved data from a manufacturer can be incorrectly accomplished.

Now some regulation rewrites may be needed; they’ll be in response to these changing times. They’ll go out to industry through the NPRM process, so when you see them, read them. They’ll be submitted for your approval. AMT

Stephen Carbone is an aviation industry veteran of 28 years. He works at the Boston regional office in the Flight Standards Airworthiness Technical Branch. He holds a master’s degree in aviation safety systems.