I would expect that.

The high utilization operators, which will be high use corporate and charter, are going to want newer equipment since equipment cost is a smaller fraction of their operating cost when spread over more hours.

The low utilization operators, which will be low use corporate and owner operators, are going to be more impacted by equipment cost and therefore will choose older airframes.

If you fly 500 hours/year, get a CJ3.

If you fly 100-150 hours/year, get a Citation V.

That works for both parties economic situations.

Mike C.

Chip, maybe you mentioned this before, but how do you define "in service"? And are those US numbers or worldwide numbers?

I've talked to West Star. That is not what they said.

I've talked to Standard Aero. That is not what they said.

I have not talked to Textron or Stevens as of yet.

The "you can't fly past TBO" FUD is common and false because folks like you spread it around.


The FAA has provided guidance that the above is not binding. Overhauls (adding new life) is never a required element of an inspection program, even if mentioned in the program, unless mandated by AD. Inspection (checking for airworthiness) is a required part.

Also, there is no task in Phase 5 that addresses engine overhaul. Just not there.

Mike C.

I don't think that adds up to $65/hour. Does the FJ44 require that much maintenance between major events?


The contract does say this:

Expenses associated with transporting non-Williams maintenance personnel to accomplish maintenance actions, expenses associated with ferrying or relocating Aircraft, or transportation costs.

Seems like the MSU cost should have been on you per that clause. It would be within Williams rights to exclude the MSU cost per the contract.


There is a list of 17 exclusions in the contract, including:

Maintenance identified as recommended per chapter 5 of the applicable Williams International Line Maintenance Manual (e.g. water rinse, compressor cleaning, heated inlet polishing, etc.).


So not everything seems to be covered. Things like starter/generators and hydraulic pumps are airframe supplied and not covered, either.


Here are the downsides to the Williams:

1. Williams can change the terms arbitrarily at contract renewal (typically every 5 years).

2. Williams can change the price every year without limit (long ago the contract was tied to CPI-W, no more).

3. If you don't fly 150 hours/year, you pay for those hours anyway (you do presently get 1 year in 5 grace, so don't ever fly 149.5 hours one year!).

4. Over a TBO cycle, the total payments are $1.7M. That is an excessive amount of money for the engines and in some cases exceeds the value of the aircraft (as is your case with the Eagle II).

5. If, at any time, you go off program, say for non payment or other snafu, the ENTIRE value of previous payments are lost. To get back on program requires paying every hour from hour zero. There's no credit for past payments.


6. You don't get thrust reversers.



The Williams plan works for some, doesn't work for others. I tried pretty hard to buy a Williams equipped plane (S550 with FJ44-3A, and a 501 with FJ44-2A Eagle II like yours) and was willing to sell my soul to them, but in the end, I decided against it and got a V with JT15D-5A. I'm glad I did for various reasons. I have come to appreciate the advantages of thrust reversers for one. Another is that my fuel penalty is not as big as I had thought, about 10-15% more, and my performance is higher. I found the Eagle II mod particularly underwhelming for performance as the fuel hump lowers the critical Mach number and limits cruise speed.



Williams does manipulate the rules to their advantage. For example, if the engine is on program, it has a 5000 hour TBO, off program 4000 hours. How the engine knows it can last longer when you send a check to Williams is beyond me. Also, Williams prices off program major engine work to be about 30% higher cost than if you had made the program payments. Basically, you have to be on the program or Williams will stick it to you.

Mike C.

Textron, West Star, Stevens, Standard Aero, and more small shops than I could possibly list here.

It says in the MM that all inspections and recommended manufacturers limitations must be complied with to sign off the phase 5.

Overhaul doesn't fall into either of those for P&W

If you go back and read what I said, you'll see that I didn't say that at all.

I said that some shops will not sign off a Phase 5 and that they use verbiage in the Citation MM as their justification.

No offense, but I've been managing Citations through maintenance events for 20 years. I have first hand experience with dozens of shops from East Texas Turbines to Textron.

Spreading false information is telling people that it's ok to operate Part 91 past TBO when that's not the whole story.

You still have a maintenance facility, possibly a lender, and an insurance company to worry about.

Not to mention the potential increase in personal liability if you did have an engine related accident.

If you go back and read what I said, you'll see that I didn't say that at all.

I said that some shops will not sign off a Phase 5 and that they use verbiage in the Citation MM as their justification.

No offense, but I've been managing Citations through maintenance events for 20 years. I have first hand experience with dozens of shops from East Texas Turbines to Textron.

Spreading false information is telling people that it's ok to operate Part 91 past TBO when that's not the whole story.

You still have a maintenance facility, possibly a lender, and an insurance company to worry about.

Not to mention the potential increase in personal liability if you did have an engine related accident.

Netjets overhauled their JT15Ds at 11,000 hours. I assure you there is nothing unsafe or illegal with operating a JT15 over its 3,500 hour recommended TBO. You do not need an STC to do this Part 91. There is clear as day FAA guidance supporting my proclamation of these facts. Any shop that won’t sign off a Phase V because of this is not being honest with their customer.

Which one?


There is no gray area. Overhaul is not required for part 91 operators even if the MM says it is. The FAA is clear on this point.

The TBO extension STCs exist solely because part 135 operators don't get the same relief so the STC was developed to give them essentially the same benefit, albeit at a cost for the STC and usually with some gimmicky engine monitor system. Just because the TBO extension exists doesn't mean a part 91 operator needs it.

Mike C.

It is possible the overhaul increases the odds of failure. Maintenance induced failures (FITs) are a high percentage of the squawks I suffer. It is also an opportunity to introduce defective parts. I know that happens a lot in the piston world (bad cranks, pistons, cylinders, etc).

I am certain the first hour after overhaul is more dangerous than the last hour before overhaul.

In reality, the hot section inspection plus life limits on the other rotating parts cover you pretty well for the things that can go badly.


Doubtful, they seem to be more ouija board than science from what I can tell.

Mike C.

I've yet to find one.


Seems like you could produce more specifics in that case. Like a person I can speak to at those shops that corroborates your statements.


That is the whole story. If a shop doesn't allow it, they need to be educated.


That's spreading more FUD.


More FUD.

Insurance only requires the plane be maintained in an airworthy condition. The FAA regulations define what that is and operating past TBO for part 91 does not, in itself make the engine unairworthy.

If a maintenance facility is imposing requirements beyond what the FAA requires, then they are making rule and that's a violation of FAA jurisdiction. The owner/operator is the person responsible for the condition of the aircraft, not the shop, and with that responsibility comes the authority to direct the maintenance.

It is in your business interest to create an aura of expertise and the specter of danger if you don't use such an expert, but this is a clear cut issue. Don't confuse people with false information.

Mike C.

For now all I have time for is to remind people that if they choose to operate past TBO, it would be in their best interest to discuss with their lender and insurance company. As Tom mentioned before in a similar discussion, I would get something in writing from your insurance company saying they are ok with you operating past TBO.

Mike’s statement that TBO extensions are “solely” for Part 135 operators is not accurate.

From the Flex TBO extension website

“Can the FLEX program be used by Part 135 operators?
While the FLEX program was primarily designed for US registered FAR Part 91 aircraft we can tailor the program for FAR Part 135 operators as well. (Acceptance by your Part 135 PMI may vary from FSDO to FSDO.)”

https://skyway-mro.com/wp-content/uploa ... 919-v2.pdf

They, of course, want to sell to everyone, part 91 included, so they try to convince you it is required.

My statement is that part 135 operators are the ones who need it. Part 91 operators don't.

If you are part 91 and buy the extension STC, you wasted money.

When I priced the TBO extension STC for JT15D-5A, it was $315K for two engines which included an HSI at Dallas. At that price, you aren't saving that much over a basic overhaul. The price was also contingent on having a "clean" HSI, extra if not, which most aren't. They also install some data logging doohickey and you have to report the data back to them.

This data is from Jim Clifford at tboextension.com. When I pointed out part 91 operators don't need to do it, Jim claimed that wasn't true via some argument about it being in the MM. I pointed him to the FAA guidance, and then I didn't hear from him again.

There is no gray area, but there is a lot of disinformation circulating around, often connected to business objectives, namely separating money from owners.

Mike C.

Question; did the FAA require you to do Sim training to fly the V?