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Aero Precision provides OEM part support for military aircraft operators across more than 20 aircraft


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Posts posted by pjvr99

  1. APU came from overhaul, ran through test cell - all good. Installed on aircraft, bleed air

    on, but no load, there is a 5 - 10psi pressure surge, small EGT and RPM flux. When a load is

    applied (eg aircon pack), it stabilizes. Removed and sent to test cell, again nothing could be

    found. Installed on another aircraft, has the same problem. Replaced the load control valve,

    but still the same.

    Anyone have any ideas ...??

  2. Believe me, it was the last thing I would suspect. However, a bit of a give-away

    was the 30psi oil pressure at 900° TIT and 75° oil temp. My thoughts were tending

    to a break/crack in the ADH front cover plate or a failure of the seal between the

    pressure and scavenge sides of the pump ....... but that's how knowledge and

    experience is accumulated

  3. ..... The strangest uncommanded shutdown i had turned out to be the T.D. amp. Engine shutdown and wouldn't start. Started in null fine and ran up to full power. Swich back to Auto and engine shutdown. Amp change cured the problem. Good luck.

    Had this one too, many, many moons ago .......

  4. Two areas to look at here:

    1. left hand harness could have broken wires on the speed switch c/plug. Swap it out,

    see what happens;

    2. a little more difficult to determine, but maybe a bad tower shaft, bearings, or gears. Hook a direct

    reading gauge to 5th/10th stg bleed valves, and run the engine. Pressure should be same

    as CDP, but could be as much as 10psi lower. The thing you're looking for is flux exceeding

    about 5psi. At the same time keep an eye on TIT and fuel flow. excessive or erratic fluctuation

    would give an idea

  5. On a whim today, I did a TIT calibration. Shooting TIT from the T-block, starting at 50°C and

    incrementing 50°C up to 1100° all readings within 2°C. Before and after indications of OAT,

    TIT and fuel temp was 30°C, 31°C and 34°C (fuel was higher because the sun had already

    gotten to the pump). I hooked up my relay and ran the engine @ 900°C and only had a 1°C

    change .....

    Bob, you you need to tell your FE's to concentrate on the important things:-

    1. Wine

    2. Women

    3. Song


  6. Ah, now that's a different game, Bob. First thing to realize is that no 2 gauges are going to

    give exactly the same reading. Next thing would be that that low down, there is no

    guarenteeing the thermocouple's accuracy. Also effect of air movement through the engine,

    swirling around the fuselage, etc. Sunrise on the left wing?

    In the test cell, GENERALLY, early morning has TIT, OAT, fuel and oil temps within 1 or 2

    degrees. Later in the day, this can change by a substantial amount.

    Why is the FE concerned about this? The TIT system measures measures combustion

    temperature, and is set up for an individual engine.

  7. Sounds like scavenge pump failure or weak scav pump in RGB. Read up Lockheed

    Service News Vol 18 No 3. An excellent explanation of the oil system and trouble-

    shooting it, which was later put out as a service bulletin

  8. Steve, you're probably right on that. The info I have only says 1071°C, with a large group

    of people saying that 1071 is a typo, and should be 1077°C..... :hands-surrender-smiley:

    In all honesty i don't know whether the thermocouple system averages or totals. The TO's

    only state that in the event of a suspected bad thermocouple the engine should be run, and

    TIT reading taken at about 70° throttle (+-850°C), then the engine shut down, the leads

    swapped over at the T-block, and the engine run again at the same throttle setting. Difference

    should not be more than 6°C (10°F).

    A dead thermocouple will cause a loss of 18 to 24°C at take off ..... (but for the life of me, I

    can't find the reference).

    I have found several broken thermocouples over the years, but only on engines that had

    already been removed for burnt turbine or some other maintenance leading into a -6

    inspection. Most time maintainers don't really troubleshoot TIT problems, just run a yellow

    box or adjust the TD valve.

  9. Hey Bob, I got your PM but things a little crazy. I don't really understand what 'anticipation'

    has to do with the TD valve. Below cross-over (temp limiting), it is just an over temp

    protection, while above it controls at the temperature set by throttle input.

    When doing the 'Yellow box' (TD system calibration), step 9 and 18 give 14 seconds as a

    response time for the valve/motor to move from a given setting to NULL. This can be easily

    verified when doing a TD system 'Controlling' check. It is possible that the motor or the brake

    was binding, and this is why the OH facility replaced the drive train.

    Hope this helps


  10. Bob as far as I can tell there is no TIT difference between engines. T56-A15 needs to

    make 1067°C to 1083°C in auto at take off, minimum 1007°C in null, with the overriding factor

    of minimum torque for the given altitude, OAT, runway length and take-off weight. D22A needs

    to be 1077°C (or as close as possible) in auto, 1007°C in null.

    I built a switching device for our test cell to switch the AMP and IND leads at the T-block, so

    we could check the difference when we have unusual TIT indications (works really well). Haven't

    yet found a bad thermocouple, though.

  11. Some time ago I was inspecting a QEC kit, and saw the bolt had been turning, and

    subsequently worn its cadmium plating out. I tried to find info on this as there was evidence

    of sealant which had been removed. A fruitless search as it turned out. I measured the holes

    to ensure there was no other damage or wear, fitted a new bolt and nut, and put sealant


    My feeling is that the sealant is not so much to seal something, as it is to prevent the

    bolt turning ........

  12. Excerpt from a post by Phone Wind on FlyAfrica ......

    There are reports that a Nigerian Air Force C130 crashed at Port Harcourt International airport yesterday. The plane was carrying 30 staff from the Nigerian Emergency management Agency, NEMA, on a mock rescue exercise and waiting airport emergency workers instead found themselves involved in the real thing. The aircraft turned hard right off the runway when about half way along it and has been severely damaged.

    From a newsclip taken inside the aircraft by a Nigeria Television Authority cameraman who was onboard to film the mock rescue, it seems that the passengers had trouble using the emergency exits when trying to leave the aircraft and it also seems the firetrucks were using water rather than foam. According to a report in the Guardian newspaper, "people were waiting so that when it gets down, it can stop abruptly on the runway so that they can rush down to rescue in a mock manner, but then it vied off the runway.".

    The aircraft was closed to both air and ground traffic for some hours and Hind gunships from the Port Harcourt NAF Base flew in military personnel. Some of the injured were flown out on the evening Arik Air flight but were banned from talking about their experiences.

  13. Hi Bob, long time, no chat. I get a rash of these things from time to time.

    First thing to determine, is it the whole schedule that has shifted, or only start?

    Are you getting this problem in NULL and AUTO?

    What is the RICH/LEAN spread?

    Are you making 1077°C take-off in AUTO?

    What is NULL take-off, will it make 1007°C (minimum), or does it exceed 1083°C?

    Let's see if we can beat this one



  14. Been working these engines on-and-off since 1985, about 15 years in total time. It's as

    reliable as YOU make it, but it is a simple tried-and-tested power plant. Learn the TD system

    and the oil system, especially the scavenge, as these are most likely to bite you. Safety

    wiring in the QEC can be a b!tch, but you learn to work around most of these problems.

    Welcome to Herks!!

  15. Shotgun propellant overcharge/compressed charge, magnum primer, and over crimp - recipe

    for disaster. He's lucky he only lost a little blood, and not his hand. Alternately, the metal

    between the chambers shows a little oxidation and what seems to be striation ..... maybe

    a crack or cracks, or some metal fatigue ......

    There's a lot of things that can go wrong very quickly when you're reloading. One of my

    favourites when I started, was cases splitting. I loaded 9mm Parrabellum using an 85gn

    bullet and around 7.5gn of shotgun propellant to get the energy up. Result was the cases

    seldom made 3 reloads before the case split or primer pocket became too worn out. My final

    competition load was a 150gn bullet and 4.8gn of propellant - smooth and soft on the hands,

    and with a subsonic muzzle velocity, easy on the ears too

  16. To answer the question, nothing they are one in the same...

    The breakdown...

    L82 is the basic model number for all C130/variants, but they also have expanded model numbers as well...(Not all Lockheed aircraft have the expanded numbers, IE the P3)

    The expanded model numbers...

    L182 - all Alpha's, and mission specific varants

    L282 - all Bravo's and varants

    L382 - all C130E's / L100's and later aircraft, including the stretches.

    Lockheed started a version number as well, not sure if it was at the start of the Jaybirds, before or after, but they are used on the F/A-22 as well. Though not sure if anyone will see/know these other than those in the plant won't waste time typing those.

    C130, C130-30, L100-20, L100-30 is what is called the aircraft type.

    Other examples of Lockheed Model numbers are

    L22 = P38 Lightning

    L85 = P3 Orion

    L88 = L188 Electra

    L93 = L1011 Tristar

    L645 = F/A22 Raptor

    Thank you kindly sir. I figured it was that, but office-types don't want to believe it .....

  17. Two questions guys:

    1. Whst is the difference between L100 aircraft, and L382;

    2. does anyone know if there is an IPB for the 501-D22A available

    in .pdf, and if so, hoe can I get a copy in a hurry?

    Thanx in advance


  18. Sounds just like Ryadh when I was there with ELF 1. Only thing that was left out was any accident you're in is your fault because you're the American and if you weren't there the accident wouldn't have happened!

    Not much has changed. I have heard the IOC (Olympics) is considering upgrading

    driving in KSA to a full-contact sport :-)

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