Torque

[mm130b]

At take off no 1 eng less torque 1500 in lbs than no 4 eng while fuel flow and tit same but below xover torque equal.anyone can help me.

[Lkuest]

Calibrate the torque indicator. It should be about 650-700in-lbs (roughly) in low speed ground idle with no load and the lowest power setting with the throttle. You should also check the torquemeter pickup for proper shimming and condition.

It could be bleed air related. A Man-On-The-Stand run could help with that.

It could be an anti-icing system malfunction. Operate engine at LSGI, close the bleed air valve to the engine, cycle inlet anti-ice a few times. If you get a 24 degree difference, everything is good. If you consistently get below 24 degrees, you could have a malfunctioning engine anti-icing system, and troubleshoot that.

An alternate method is to advance power up to 850 degrees with bleed air valve closed and TD switch in auto, then actuate engine inlet anti-icing. You should see between 900 and 1400 in-lbs change. Any less, and your system could be malfunctioning. In either case, it wouldn't hurt to reseal the engine inlet anti-ice valves mounted on the Air Inlet Housing. The seals inside love to shrivel up.

You may also have a TIT indication malfunction. The easiest way to tell is to perform all the TD system checks, such as start TIT, Crossover TIT (800-840TIT for -15 engines), Max TIT(Load the engine up with a bleed air load to ramp the TIT up), and TD Valve Brake Lock check (1084-1090 TIT). If all of these checks are skewed, then the TD amp is either mis-tuned or there is a difference between what the TIT indicator is seeing and what the TD Amp is seeing. In this case, look at the entire TIT indication system and TD system.

You could have a combination of these, as there are many places for air to leak on the motor, and the TD system isn't extrememly reliable. The worst case scenerio is that you have a bad turbine or bad compressor. Borescope the turbine. Your engine could also be worn. The life of a typical turbine is about 5,000 hours (someone correct me if I'm wrong), and the compressor I believe is about 6,000 hours. Pull the 5th and 10th bleed valves and check the compressor blades for curling or build-up. Check speed valve filter for clogging. Check Compressor Discharge Pressure, and then check performance between motors with the bleed air valves closed.

We've had a similar problem caused by a high-efficiency compressor pulling low power because it was running all the bleed air systems single-handedly. If you have bleed air regulator valves, you shouldn't have that problem.

Please let us know what you find:)

[NATOPS1]

First I would as "Lkuest" said "Calibrate the torque indicator." then calculate the Torque you should indicate when you set a certian TIT. (performance manual)

To rule out other systems use the no bleed correction chart. (+600 inch lbs)

Set your TIT you calculated for with the engine bleed air OFF and see if you have a problem.

If this engine is at 95% and the others are all at or above 100% then it looks like a problem but may not be.

[pjvr99]

1500"lb difference should not be a problem, unless both engines had the same torque

on previous flights. This difference is worth about 7.5% performance. If previously the

same, I would hazard a guess at a scoop anti-icing valve failure - the numbers are

fairly consistent, and a 50pph fuel flow difference would be hard to spot during take

off ..... all of Lkuest statement is true

On the scoop valve, I had one several years ago that worked great below

about 850°C TIT. Above that, it would open and had me hunting a TD system

malfunction for several hours.

[alioman]

thermocouples maybe ???????????????????????????/