pjvr99

This one has the grey matter in a mess (more so than usual). For the numbers to change

that radically, you need the TD and the FCU to work together. I'm wondering if there isn't

a split pulley or tension regulator stirring the pot. Also take a good look (disassemble) the

gimble assy at the coordinator.

Also take a look at the CIP hoses for blockage, both upstream and downstream of the FCU,

blow them out with compressed air

well at least you know the problem is in the kit (somewhere)

The wire pairs for the reference and torque signals are shielded, and grounded on the torq

indicator. A break between the shield and wire can cause a misread. Had the same thing

late last year. We had disconnected the tm pickup cannon plug, and the Misc2 (?) cp and

had a 20MOhm reading to ground on pin A of the tm cp, where it should have been open

circuit. Hope this helps .......

Pack it up - ship for overhaul ..........

..... the little motor in there simply isn't strong enough to overcome the brake?

That's the operating theory, but every once in a while, the TD brake lock test

passes, but fails TD system check by losing TIT and fuel flow when the switch

is moved from AUTO to LOCKED with the anti icing on. Even though the brake

may indicate LOCKED, the valve may still slip away to the NULL position ......

During aircraft decent (landing)rpm fluctuate 99%-102%.normal flight rpm no fluctuate.td valve null,propeller mec gov position also fluctuate.tit,fuel flow,torque normal.

Anyone can give solution.

I'd hazzard a guess and go with NTS'ing. However, you're at flight idle/low pitch stop, so rpm will be below 100% (out of prop governing). Alternately, if there is no other indication, it may just be a bad tach generator ....

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.

..... but I'd need to know what all the other instruments are doing .....

I agree - not enough info

Filter 8psi

FHS 12psi

Cooler 10psi

Filter outlet also should not exceed 30psi

Now: older type oil coolers (full oval face) below 75°C give a differential of +-8psi, but

happily rise to 18psi above 75°C. Newer type (square face) seldom have a differential

of more than 8psi, but often have trouble keeping the oil temp below 85°C on very hot

days. The question becomes 'do you go by the book, and reject cooler after cooler for

high back pressure', or, 'get the back pressure right, but have high oil temp problems

in ground range on hot days'?

Bearing in mind, that high back pressure can lead to oil dumping at altitude. What I would

suggest is get the engine onto the test cell, and check out the scavenge system; i.e. is

the RGB and power section scavenging all the oil back from the various sections. Check the

indicated difference in qty between running at 900°C and immediately after shutdown. Also

check indicated qty at LSGI and NGI with the oil temp at normal running temperature. Check

residual quantities in RGB and PS by draining and measuring immediately after shutdown. Make

your decision from there ......

Oil cooler the most likely culprit, but if the #2/#3 bearing pumps are not doing their job (or any

of the other scavenge pumps), high oil temps do result. Easy way to check this - run engine

at 900TIT and note oil qty, check the qty after shutdown with engine stopped. The difference

should be less than 2 gallons. Old dirty oil has also been known to cause high oil temps

No other flux indication, I'd take a look at swapping tach generator, moving the tach gen

to the alternate drive pad, or even onto the speed switch ........

less air requires less fuel.

Remember your ideal air fuel ratio for combustion = 15:1

Sounds like the speed sensing valve failed, opened 5th & 10th stage bleed valves .......

Also APU FCU cannot compensate enough for altitude/temperature change. Even big

commercial aircraft are limited to about 15000ft. It may run at higher altitudes but will

flame out at the first application of load - even a shift in generator load can be too much

What NATOPS1 says. Null/auto TIT, before/after light out TIT at X-over, and rich/lean TIT

TO 2J-T56-56 SWP 060 00 Troubleshooting Table 57: Replace thermocouples.

If this doesn't work, do an OHM's check on the coordinator potentiometer.

Last, if this is an ABB or other solid state TD amp, have a go at swapping it out

So there we were, an engine giving 104% performance, 29.85"Hg air pressure,

and 20°C OAT. Engage the pitchlock, push the throttle to take off. Watch the

overspeed at 105% rpm, fuel flow at 1500pph, torque around 10000"lb.

Next moment fire warning light flashes on, fuel flow shoots to 2000pph, torque

rising rapidly, and rpm on the way down. Then everything goes back to pitchlock

settings, ....... and again the fire warining, and fuel and torque rise, rpm drop, and

back again.

Fighting the instinctive throttle back to prevent overtorque/flame-out situation while

pitchlocked, yet still trying to analyze the situation, I finally opted for feather shut-

down.

Lots of extremely wide eyes in the control, I find myself thinking "double rum and

coke would be good about now", and realizing that I'm in the Magic Kingdom. So

reset everything, cool down the engine and start up again. Everything all happens

again except this time there is no response on the throttle when I tried to throttle

back. Another feather shut down!!

Decided that because the engine had been standing unpreserved for a looonnnggg

time, it must be the fuel control governor that cr@pped out. One FCU change later

and we try again. Initial pitchlock check good - joy!! 20 minutes later (and another

feather shutdown), I'm shaking from adrenaline overload.

After consulting with the prop shop brains trust, the decision was made to replace

the valve housing. Again everything checked good, with 3 back-to-back pitchlocks

successful. Work through an entire run sheet, and get to the pitchlock step again,

back to square one!!!

Slaved in a spare prop main control conduit - no change! Started investigating the

test cell cables and junction boxes. Finally found the 'sync box' of the test cell had

a burnt component. The main control and the fire detector leads run in the same

harnass. So I'm guessing damaged wires inside the harnass shorted between the

prop control and the fire circuit.

Disabled the fire circuit and replaced the prop control box, now everything is

working as advertised. My arms, however, feel like I've been wrestling bears or

something .......

Difference in torque at FI when throttle is moved from GI to FI, and

when moved from above FI back to FI. Difference should be a

minimum of 500"lb (200"lb on some special variants). Sometimes a

failure will be indicated by no difference, while the torq may hold for

a few seconds when coming back to FI, before dropping off. Also in

static operation, no hesitation at LPS angle is noted on protractor

when unfeathering to GI or Reverse

Anything in mist form with an air/fuel ratio of about 15/1 will burn. MIL-PRF-83282 is

supposed to be less flammable than MIL-H-5606. Least flammable is really sh!tty

stuff used by Boeing, known as SKYDROL

http://www.airplane-pictures.net/images/uploaded-images/2009-4/19/42924.jpg

All still at Al-kharj, apparently in bad shape

I once got a center right window that the heating elements had broken. I set

it up at my local shooting range with some paper targets behind it. 5 shots

with a 9mm P, 3 with a .45ACP, a 2 with a .357 Desert Eagle didn't penetrate,

but made me think seriously about being crew. The paper targets behind were

shredded!!! Hail and birdstrikes shouldn't be too much of an issue, as mostly

the window will either deflect or the whole panel will be pushed in; small diameter

high energy objects turn the inner layer into a shrapnel storm of note.

Given engine rigging is good, check the backlash screw in the VH cover is tight, and

take a look at repositioning the input shaft micro adjustment.

RPM is determined by the prop governor. Throttle position around 55° - 60° on the

coordinator is where the prop will hold RPM at 100%. Below that the blade angle is

mechanically determined by throttle position, and RPM is merely a function of fuel

flow vs blade angle. New strong engines tend to run around 97% - 97.5% at GI,

while older weaker engines tend to 96%. FI is around 96.5% on new engines, while

older engines go to 95%. Top-of-Beta is +-0.5% lower on older engines than on new.

There is nothing I know of to change this, given all engine and prop rigging, and

blade angles are correct. It does happen from time to time that RPM's at these

positions are lower than expected, but bear in mind your limitations:

TO 1C-130H-2-71JG-00-1 71-00-02

Normal ground idle RPM: 94% - 102%

Flight idle RPM : 92.5% - 100.5%

Sometimes a crew change also makes the problem go away :-)

There is a LOT of things that can cause a pulling problem, props 'n engines often being

the first accused. Take a good look at the MLG: shelf brackets, torque link, guides,

rails, etc.

To add to Lkuest, check magnetic plugs on RGB and P/S. Also do a fuel governing & pitchlock

check - unstable fuel flow, rpm would indicate a fuel control failure. If you're going to try

another flight or FCF, close the bleed air valve and see if the problem persists.

A very long time ago, I had an engine that had a torque flux below X-over. The engine was sent

to overhaul, but when it came back it still did the same thing .... but worse. The next time it

came back with the report of a problem with the towershaft bearing. What was happening, it

was intermittently missing a tooth on the gearing, and the speed valve was popping open. Above

x-over, the TD system was strong enough to smooth out the problem. I only knew about the speed

valve opening because I heard an intermittent hiss during a man-on-stand check.

As Lkuest says, there is any number of things independently or in conjunction, that could cause

this. Let us know what you find.....

http://herkybirds.com/showthread.php?1538-Throttle-Creep

This problem was previously discussed on this thread ...... in this one case, the

loose shaft was spotted by my apprentice. Seems if there is enough bumping

around, and you've done every other thing you can possibly think of you have

simply removed almost all system resistance, and even that small movement can

cause the throttle to creep