Poll...TFE 731 inflight shutdown

[Pilot_Ryan]

Speaking of which, at Simuflite I've heard a couple of times that there has never been a TFE731 involved in an inflight fire. Anyone know if this is true?

 

[falcondriver]

I have had more problems with the computers than the engine. Our computer on the 731 AR spooled back the right engine to idle at 410 on our Falcon 20. The Hawker would surge the right engine 10 %. We would have to go to manual mode to stop it. They would fix it and as soon as you got comfortable it would do it again.
I was told the same thing about no true fires.

FD

 

[Lead Sled]

Speaking of which, at Simuflite I've heard a couple of times that there has never been a TFE731 involved in an inflight fire. Anyone know if this is true?

There have been plenty of false indications, but until recently, no fires. I seem to remember something about a recent one in Westwind, but that may have been something else. It's pretty hard to stay awake in groundschool.

'Sled

 

[some_dude]

3,000+ hours in 731s in Lears, Falcons, Westwinds, no failures. A couple of minor computer issues but that's it.

Now, of course, I've jinxed myself...

 

[suen1843]

The 731 seems to have gotten a pretty good reputation for reliability lately, but when it was first introduced it was a POS. Early Lear 35 operators always had a CJ powered LR25 follow them around with a spare 731 in the back.

A lot of newly introduced engines have problems...the original PW305 and ALF 500 series come to mind. Also, ask some of the 2000EX guys what they think of the upgraded Pratts. Lots of replacements there already.

 

[banned username 2]

All but about 500 hours of my 5,500+ hours of Jet time have been on TFE-731's from the -2B, to the -3AR, -40 & -60 (Lear 35/55, Falcon 10, Citation III, Falcon 50EX, Falcon 900EX)... I personally have only shut one down, it was a -40 back with the early carbon seals, had a couple computer issues on the -40 and -60 as well, but nothing more major than that... Next month I start running a pair of BMW/Rolls-Royce motors, will be fun to try something new...

 

[yfly]

Lost a 731-2, a bearing in the planetary gear box decided to take the day off. Lost oil pressure and the engine seized before we could shut it down. We were at cruise, 27,000'. Couldn't have planned for a better time.

 

[Falcon Jet 1]

Had the same surging problem in our westwind years back, an finally found it to be a loose wire on the pt2tt2 probe, drove us nuts as well until our mechanic did his job and isolated to the probe. we initially switched computers but the problem stayed , so that is what let him isolate it to the probe

 

[EAP]

Interesting. Similar surge problem (was doing it at cruise in a narrow ITT range), same loose wire "fix" on the Pt2 probe. It was rock solid the whole time after the fix - flew it for about 100 hours afterward, before I parted ways with the airplane.

 

[LegacyDriver]

When I was flying C-21's in the military, we had roll-backs on the TFE 731-2-2B's all the time. The engines would go to idle at all the most convenient times - during take-off roll, first turn in holding and so forth. After installation of the DEEC's the engines quit rolling back, they just quit instead.

GV

That sounds like the boys with the slide rules missed something when they came up with *that* fix!

 

[flyinlow67]

Do the problems with the 731's seem to be aircraft specific or engine specific?
We have them on our Sabre 65's, but I am just starting to learn the aircraft and don't have a ton of experience in them quite yet. Haven't heard of a whole lot of problems in our birds.

 

[SabreFlyR]

Do the problems with the 731's seem to be aircraft specific or engine specific?
We have them on our Sabre 65's, but I am just starting to learn the aircraft and don't have a ton of experience in them quite yet. Haven't heard of a whole lot of problems in our birds.

The last flight in a 65 I was flying last year the the ITT ran away and had to be shut down. Not sure what the fix was, like I said it was my last time in this plane, but pretty sure it was those fine deec computers that were just installed.

I have 2000 hours in a Westwinds, only had one that had computer problems, a couple with oil pressure problems and two with bad carbon seals that put the familiar oil smell in the cabin.

 

[westwind driver]

Vegetto,

I experienced a similar event in a Westwind. TFE731-3-1Gs on that bird. The only difference is that we did not have DEECs. We were purchasing the aircraft and were going for a test/shakedown flight. L/H engine would not produce N1 t/o power with the EEC in NORM. We turned it off and sure enough got the power we needed out of it to fly. We taxied in, set the EEC in the back to run in MAN mode so we would have overspeed protection etc, and proceeded with the flight. We did another flight with the EEC in MAN, and after climbing out we placed the EEC in NORM. The L/H engine did the same sort of surging you described, with a pronounced yawing motion.

Brining the aircraft back home from Europe we had to fly with the EEC in MAN for a few minutes to allow it to reset itself on each leg.

It was one of the weirdest damn things I and the other pilot have ever seen.

BTW, we had a new EEC installed after the first shakedown flight and even the new one acted in this manner. Who knows, sometimes I think some aircraft or parts thereof have gremlins.

We'd fly along and (WAH-WAH, WAH-WAH, WAH-WAH) go to MAN on the computer for 5-10 minutes, back to normal and it wouldn't give us a problem until the next leg.

The aircraft now has DEECs on it and we haven't flown it since it went in for refurb.

 

[westwind driver]

My first job on a Westwind was as an SIC on a II. It had the digital ITT readout that has the "H" light up when the temp reaches 885.

Because of this, the PICs I flew with believed as long as the "H" wasn't lit up, it was OK. (The climb limit of 870 and the cruise limit of 849 often ignored.)

One day the "Fuel Controller Manual Mode" light comes on the left engine and I get the checklist. The PIC saw that it was over temping and shut it down, but it was too late. We landed and there was a stream of metal particles coming out the tailpipe.

Another Westwind I flew had minor fuel controller malfunctions (going to manual mode) but nothing particularly disturbing.

I was told once by an old hand that the reason the MSP program came about was the high unreliability of these engines when they first came out. Duncan told me these engines tend to be very beat up when coming off Westwinds and Hawkers, which I suspect is from pilots running them hot to try to make the plane go faster.

In my opinion the one thing you must do with these engines is always carefully observe the temp limits. That's ture of all engines but my impression is these are more sensitive than most.

870 degrees in Simuflite's recommended climb setting, as to not over-speed the N1s.

you can run the TFE731-3-1Gs on the Westwind at 885 degrees for 30 minutes during a single cycle. You can run them at 907 degrees for 5 minutes. I think 907 is only possible with EECs, I believe the DEECs will MAX out on the N1s first.

Anyway, Simuflite recommends running the power at 870 during the climb up to FL300, then allowing the ITTs to creep up to 885 and only adjusting throttle position as to not overspeed the N1s.

Our department proceedure is the above, we allow the ITT to creep up to 885 while not exceeding 101.4% N1.

While we run our engines hard in the climb, they were designed for that, once we reach the 30 minute mark, we pull the power back to 849, then look into the simuflite book to get a fan speed for our flight level/weight/temp for a constant mach cruise.

Sometimes we might be at 849 on the ITTs for an hour until we burn off enough fuel to start pulling the power back for a .72 cruise. (Example of a West coast trip, and we fly 4 hours 40 minutes and land with 2200 Lbs, no AUX tank, WW1)

 

[ultrarunner]

Sounds like we lost the carbon seal and then the bearing very quickly.

Now there's a shocker!

I lost lost one when the O ring failed on the #7 bearing. Starting loosing pressure, and when the light went off, we shut it down.

Yep, good 'ole 731's.