More on Engine STCs
Trying to develop a TBO extension for the Rolls-Royce Spey and Tay engines
By Joe Escobar
Last month, we discussed the MORE STC program for TBO extension of PT6 engines. This month, we will discuss another engine STC program in work that would give operators of Rolls-Royce Spey and Tay engines some relief.
Dallas, Texas-based Business Jet Services Ltd., a company providing on-demand air charter services and management services for corporate aircraft owners, has been working on an engine STC program similar to the MORE program that would give operators of Rolls-Royce Spey and Tay engines relief from TBO requirements while at the same time increase safety and reliability. I recently talked with Kevin Jordan, a partner with Business Jet Services, to learn more about the progress of its STC.
When Business Jet Services received its charter certificate, one of the aircraft it operated was a King Air 200. One of the engines was on the MORE STC program, and the company soon realized the benefits of an STC like this for engine operators. The wheels got spinning on how it could develop some type of program for Spey and Tay operators.
Spey TBO requirements
The Spey engine has a 10-year, 4,000-hour TBO limit. At the first 10-year cycle, it has to go in for a mid-life inspection, and at the second 10-year limit, it must be overhauled. This can be a big financial hit with mid-life inspections costing around $800,000 and overhauls running from $900,000 to $1,200,000.
Jordan discussed the TBO requirements. "We got to looking at this whole thing, and I said, 'You know, why in the world, is this the only jet engine out there that has a 10-year calendar limit on it?' Gulfstreams are a big part of business aviation and charter fleet. And realistically, we wanted to look at some way to dilute this big hit that Rolls keeps putting on us. So we looked at changing the requirement from the existing 10-year, 4,000-hour limit to on-condition, no calendar or hour limitation. We would accomplish this by more closely monitoring the health of the engine."
Getting the process started
So a team was put together to look into developing an STC solution for the Spey engine similar to the MORE program for the PT-6. A team of experts was assembled to spearhead the effort. "We put together a team to work on the program," Jordan explains. "It was comprised of a retired American Airlines powerplant engineer that supervised the maintenance and overhaul of the Spey and Tay engines for American when they were on condition on the BAC and the F-28 Fokker. We also had a retired FAA guy, A.C. Caviness, that used to head the engine division of the FAA for this type of thing. We also included Jim Fackler who is a vibrations analyst out of California who was the vibration expert on the MORE program, Don Stroud, a DER based here in Tulsa for regulations, and my director of operations Rob Irwin, as an FAA liaison."
Beginning the test program
The company initiated a comprehensive test program to gather data to support its proposal. This part of the legwork took about a year to accomplish. Research and testing were carried out. All of the company's aircraft were put on a model program to establish baseline data and engine readings. This was done while also adhering to existing manufacturer requirements.
The Spey and Tay STC would include additional inspection requirements for the engines as well as tight inspection intervals. An engine monitoring system, developed in conjunction with the Shadin Corporation, would be installed on the engine. "This modification monitors engine temperatures, speeds, and all engine parameters," Jordan explains. "It assimilates all the information and is downloaded to a disk that can then be entered into a trend monitoring program that would look for anomalies, spikes, and deviations, and alert the operator if there is something about to go wrong with the engine.
"This program is not designed to be a 'get out of jail free' ticket for operators," Jordan explains. "Its goal is not just to extend the TBO life. It is a comprehensive program that can more effectively monitor the health of the engine and spot defects in a timely manner. We expected that we would have to closely police this and monitor it. And we are going to find things wrong with the engine ahead of time. But that's what you really want to know. And now if you eliminate that 10-year calendar, what you can do is go into the engine, repair it, and put it back in service."
As one example of the benefits offered by this program, Jordan shares the following. "Rolls-Royce had done away with the routinely occurring borescope inspection. Of the six engines that we put on our test program, we discovered problems on three of them with our borescope inspection that would not have been discovered on the Rolls-Royce program."
On to the FAA
After a year's worth of testing, research, and development, the company had all its ducks in a row, and was ready to work with the FAA on getting STC approval. It submitted its package to FAA engineers in Fort Worth. Initial feedback from them was "It looks good." But then Business Jet Services received a rejection. "They rejected us," Jordan says. "They just closed the book on us and rejected our application.
"So we did more work," Jordan explains. "We wrote more letters, made more calls. We sent our package to the FAA guys in Boston, which is where all of this was coming down from. We hired APCO which is Jane Garvey and Peter Goules (the retired NTSB guy) consulting firm. Peter brokered a meeting with FAA in New England, and we took the whole team up to Boston and met with them. This was six months after they received our manuals. We sat down with them and they had never cracked the book. They had never read anything. They just outright rejected us and said that an STC is not the proper way to do this."
Unlevel playing field?
This whole situation demonstrates an unlevel playing field on many parts. First of all, the FAA is telling Business Jet Services that an STC is not the proper way to accomplish a TBO extension, yet the same division has previously approved a similar STC in the MORE program. "The MORE STC on the Pratt & Whitney PT-6 engines increased the TBO from 3,000 to 8,000 hours with far less sophisticated monitoring and inspection procedures than our program proposes," shares Jordan. "The MORE fleet of engines has experienced no safety related issues and approximately 3 percent of the MORE fleet to date has safely reached the 8,000-hour TBO limit. Contrary to manufacturer's predictions, the operators of those engines reported no abnormally high overhaul costs at 8,000 hours vs. their previous 3,000-hour overhaul requirement."
Second of all, if the FAA is concerned with how TBO extensions relate to safety, then why does it allow Part 135 operators to operate the same engines with extension programs? "The Spey and Tay engines utilized on corporate BAC 1-11's and Gulfstream II's through IV's are the same engines that were (and are) operated on-condition by American Airlines, Braniff Airlines, U.S. Airways, Horizon Air, and others for years with no detrimental results," Jordan explains. "Rolls-Royce requires us to do the 10-year inspection. But then on the other side of their mouth, they say if you are an airline, you don't have to do it. Rolls is the one that gave it to the FAA. The FAA took its advice. It is basically a service bulletin."
But according to Jordan, there are cases where the FAA has granted extensions to the 10-year requirement. For example, the Anchorage FSDO approved a GII operator's program that gave him an additional two years and 1,000 hours.
Jordan shares his frustration, "Tell me another engine that has a 10-year on it. Challengers, there are thousands of those engines, the GE and Lycoming Challenger engines. They don't have it. How many Garrett 731 engines are there out there, 10,000? They don't have it. You can fly it one hour every 50 years and you don't have to do it. We would welcome the FAA to tell us if it wants more frequency, different procedures, whatever. Instead, they just said, 'No, you're not going to get it. An STC is not the way to do it. We've done it in the past and it's a mistake.'"
"Our program is based on sound 21st century technology," says Jordan. "It's not some crackpot deal. And it's also something that the FAA told us all along that 'yea, this is a doable deal, yea this makes sense, yea, other people have done it.' Then they just shut the book on us."
More on the corrosion issue
It appears the FAA is also concerned with engine corrosion. Jordan shares a few thoughts on this subject. "We used six airplanes in our test bed. In addition, we've owned several Gulfstreams over the years and have done a number of mid-lifes and overhauls, and we submitted that data to substantiate our STC. Because the FAA is blaming it on corrosion. And when you get to researching all that data on the overhauls, no significant corrosion shows up."
Business Jet Services is now pursuing political and legal avenues for its STC.
Business Jet Services will be at the NBAA Convention in Orlando, Florida, this month passing around a petition to all operators to sign. In addition NARA has approached Business Jet Aviation with interest in getting behind the continuing effort. Stay tuned as more developments arise on this effort.
Business Jet Services
8611 Lemmon Avenue, Dallas, TX 75209