Pratt & Whitney PT6 TBO Recommendations and the FAR Part 91 Operator … the Discussion Continues

Pratt & Whitney PT6 TBO Recommendations and the FAR Part 91 Operator … the Discussion Continues

D14-KAp10The December issue of King Air magazine containing my article has created the biggest amount of pushback that Tom Clements said he has seen in a long time. I am amazed

at the number of calls, emails and letters that I had received.

It has really been gratifying to know that we can still spark a good debate amongst pilots, instructors, owners, operators, and maintenance personnel, and come to a well-researched and well-documented conclusion from our peers in the industry.

I have come to find that this is a debate that has been ongoing for well over 50 years with different views, different opinions, and different conclusions. One conclusion that I am sure everyone will agree on is that every FSDO is apparently “individually owned and operated.” Even though we have the same set of standard rules, the interpretation of these rules seems to never be the same.

During all of the discussions after the article, a very important document came to light submitted by E90 owner/operator Steve Wagner. Steve brought to the surface FAA Order 8620.2A (page one* shown in Figure 1), effective 11/05/07, which really takes the weight out of a lot of documents that I personally believed carried mandatory guidance for the industry. I have now come to find that these documents carry very little weight. I had not seen the FAA Order prior to receiving it. I now totally agree that this is a very important game-changing bit of information.

After digesting order 8620.2A, I can see where I was wrong in my interpretation of the power that a Type Certificate Data Sheet (TCDS) carried. It makes me wonder what other documents are out there floating around that negatively impact the credibility of what we were taught in class as students and as we progressed into the industry.

I now must reverse my conclusion and opinions voiced in the original article and agree with Tom Clements, Jack Braly, Steve Wagner, and others, that you can indeed run a PT6 past the manufacturer’s recommended TBO as a Part 91 operator. (Wouldn’t it be nice if our government would make a simple, solid statement like this?)

With that being said, there is another issue that I want to address. Several of the calls that I received after the December issue were from various maintenance facilities and some individual A&P mechanics. The concern that was voiced is that while you may be perfectly legal in running an engine past TBO, there is a very high degree of uncertainty as to how you now maintain that engine. There is nothing published in any of the manuals for a maintenance facility to continue to abide by after the TBO is exceeded. If you’re on the MORE program, then you have established criteria to go by. But what do we do at the 3,600 hour mark? Do we perform another hot section? When do we execute another hot section now that we have exceeded TBO?

86202A-p1
Figure 1: Page one of FAA Order 8620.2A.

Of all the maintenance professionals I spoke with, this was the biggest concern. They are concerned that now the liability for the maintenance of that engine is falling on their shoulders and there is no clear course of action for the company or individual to take to give them the comfort level they desire.

I believe that this is coming from the fact that facilities are now being found liable in court cases once they sign off an engine that has been past the recommended TBO.

As maintenance professionals, we all want to keep the aircraft that we maintain as safe as possible and as economical as possible, but no one really wants to assume unrealistic liabilities in doing so. I think in the future you may begin to see maintenance personnel and facilities just not wanting to work on aircraft that have engines exceeding TBO.

Ironically, in my entire turbine customer base, I do not have a single customer that has requested an exceedance of a TBO.

In conclusion, I originally asked Tom for documentation that would counter my assessments of the FARs and it has been provided. I therefore very respectfully thank Tom and you others who have done so. I stand corrected.

Let’s now have even more fun with the FAA definition of the “Current Manual” and how it is applied to maintenance!

Respectfully submitted,
Michael E. Stanko

Editor’s Note: For Order 8620.2A in its entirety go to www.faa.gov/documentLibrary/media/Order/8620_2A.pdf

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