Poll...TFE 731 inflight shutdown

[LJ45]

How many people have had to shutdown or had a TFE 731 fail?
How many hours with the TFE 731 before this happen?

I had my first yesterday at 3200 hrs. of flying with these types of engines.

Thanks,

 

[gear_guy]

Has'nt happened yet.

Lets hear the details

 

[LJ45]

Has'nt happened yet.

Lets hear the details

Climbing thru 16,000 in our Learjet 45, we got a high oil pressure caution, chip detect, smell of something burning and a loud grinding noise. All of this in about 15 seconds. Shut down the engine came back to our home base where we await a loaner engine. The engine is hard to rotate by hand and the chip detector is full of metal. Sounds like we lost the carbon seal and then the bearing very quickly.

Anyway, all worked out and felt like we were in sim. training.

OK, I corrected the spelling...should have ran spell check first

 

[h25b]

I've heard about the software problem in the N1 DEEC causing flameouts on idle power descents on the TFE731 but have only heard of a couple shut-downs for other reasons. NONE of the failures I have heard about were due to the core engine.

By the way, I just received an advisory wire announcing a software update for the N1 DEECS that solves the flameout problem.

 

[thatpilotguy]

I had a "fuel computer" problem that resulted in an engine run away at F410 in a Lear 35. The temp went to 920 and the N1 was racing away before we got it shut down. Sneeky little bugger started a slow temp and N1 increase for no reason. The PF and Captain I was flying with pulled back the throttle a little and that was all she wrote. I was told that is could have been nuematic icing...In anycase it was the last flight for the company before they ceased flight operations the following day.

 

[CapnVegetto]

I've heard about the software problem in the N1 DEEC causing flameouts on idle power descents on the TFE731 but have only heard of a couple shut-downs for other reasons. NONE of the failures I have heard about were due to the core engine.

By the way, I just received an advisory wire announcing a software update for the N1 DEECS that solves the flameout problem.

Used to fly a LR-35 with DEECS. Never had any kind of problem like you're talking about. Never had to shut one down either. I've only had one thing happen....and it was really f-ing weird!

Took off out of BTR one night, nasty weather everywhere. As we were climbing out through about 3000 feet or so, we felt the airplane yawing. Our freaking left engine would drop 40%, then come back up, drop 40%, come back up, drop, rise, drop, rise,......the entire drop/rise cycle lasted about 2 seconds each time it did it. CP and I were like, what the f-ck?? Hell, there's no checklist for that. Airplane was yawing, boss was wondering WTF we were doing..... Hell, we had no idea how to fix it, like I said, there's no checklist, and we didn't want to shut it down, because it was never anywhere out of limits on anything......it was just acting really f-ing weird. After scratching my head, I said 'Hey Ed, try turning off the fuel computer'. We did that, and it fixed the problem. So, we concluded it was a DEEC problem. We turned the DEEC back on at altitude and experienced no problems at all. When we got home, we had it looked at, and of course, they could find nothing at all wrong with anything. So we kept flying it, and it didn't do it again for about 8 flights. Then sure enough, there it was. Of course, once we turned off the FC switch it quit doing it, and once again, when we got back, they could find nothing wrong with the FC, engine, probes, wires, nothing. Right about then the engine was due for a hot section, so we charged Garrett in Augusta, GA with finding out what the hell was wrong, and after tearing down the entire engine, taking out the DEEC and running full diagnostics, changing out the temp probes, they STILL could find absolutely nothing wrong with anything. So we flew it home and sure enough about 4 or 5 flights later, it did it again. By then we just said f-ck it!!! We give up. Turn off the da-n FC when it does it. To this day, I have no idea what caused it, why it did it. It would never do it on takeoff, cruise, decent, landing, or anything. Only on initial climbout, through about 1000 to 4000 feet, good or bad weather, and it would quit doing it after we turned off the FC. And it would only do it once about every 8 or so flights. I don't think I'll ever know what the hell caused that!!! Weirdest thing I've ever seen.

 

[TransMach]

Garrett's Grenade

4,500 flight hours in TFE-731 powered airplanes, 2 inflight failures ...

Lots of time in GE-CF-700, Pratt JTs, PT-6, and RR RB611 ... no other failures.

TransMach

 

[PGH STEEL]

We had the same fuel computer thing happening to us in our LJ-35 Vegetto never did find out what it was.

 

[GVFlyer]

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

 

[Captain4242]

Had a 731 roll back on me a few years ago while on a short base in VFR.
Maintenance said it was a fuel controller problem.

 

[LJDRVR]

With over 2000 hours behind the TFE731, I've had the following issues:

Precautionary shutdown during approach for T/R unlock light on a Lear 35. Faulty lower DPI switch. (Banged on it with fist and light extinguished.) Crappy Aeroncas and poor maintainance. (At a 135 operator, imagine that!)

Lear 35, FL410, cabin fills with whitish smoke, no abnormal indications or annunciators. 7 minutes later we're rolling out at Philly with the fire trucks. Number two bearing failed and threw oil into the breather tube, oil coked off and filled cabin with smoke.

Lear 55, 10-15% up and down engine surge on number one during climb through mid-twenties, switched to manual on fuel computer. RTB. Faulty N2 pickup.

Somebody had mentioned icing in the pneumatics. Correct me if I'm remembering this wrong, I don't fly the Lear anymore. If the fuel computers is turned off, the FCU is evacuated of fuel. The resulting decrease in pressure and temperature can result in P-3 icing. Loss of P-3 air opens the fuel metering pin, and the engine will runaway. (Without full overspeed protection, as the the computer is off.) And yet you'll still find folks who think it's cool to save fuel on the descent by turning the fuel computers off.

The only "real" engine failure I ever had the Lear was a CJ610 that flamed out.

 

[kingaira90]

By then we just said f-ck it!!! We give up. Turn off the da-n FC when it does it. .

I had that problem with windows 2000 too! Just had to reboot and it worked fine for a couple of days, Maybe the DEEC's are windows based -kingaira90

 

[Capt1124]

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.

 

[Lead Sled]

Two in-flight shutdowns and one catastrohphic failure on the ground. Of the in-flight shutdowns, both were caused by maintenance center screwups - one engine had an over torqued oil fitting which failed and all engine oil was lost. The other was a precautionary shutdown after a false "bleed air leak" annunciator light could not be extinguished. The ground failure was caused when a turbine wheel came apart on start up.

'Sled

 

[gern_blanston]

Ahh, Garrett Grenades.
Lost a seal in a -3 back in my Westwind days. Allowed high-pressure air into the oil system. Oil pressure gauge moved just like the fuel flow gauge: More throttle, more oil pressure (LOTS more!). Less throttle, less oil pressure.
Shut 'er down and parked it.
Before I joined this company, the high-pressure compressor let go on the brand new Hawker 800 at 65 knots on the takeoff roll in Red Deer, Alberta. 60 hours on the plane.
Zero problems with the CFE's on the current plane, which are half Garrett.

 

[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.