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

tenten

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core_pfieldgroups_2

  • First Name
    faisal
  • Last Name
    al-wahidi
  1. Right hand harness; ……..Heads I win, tails you lose.....
  2. Munir; I appreciate if you inform us which wiring section is defective?
  3. Munir, If fluctuating comes only above X-over;.....Check your coordinator potentiometer.
  4. Thanks NATOPS1 for the last added safety note ; Actually for that reason, we asked them earlier not to fly or even start the engine without resolving battery issue.
  5. Thanks a lot for all responses… First of all, aircraft is on the air after replacement of both the Battery and the Bat. Relay. Flying crew upon receiving the two items elect to change both items ….. discounting our advice… for to replace the battery at first and then to check the operation of Relay). However I understand from “pjvr99” that a dead battery cannot be recharged regardless of the operation of the Relay .. Thanks “Munirabbasi” & “NATOPS1”, for clearing the main point that I was asking for (And I understand from you that: Relay cannot be energized through power coming from external, it requires a good charged battery to connect BAT Bus with Isolated Bus). “hehe” & “n1dp” our aircraft is equipped with only one battery (Lead Acid) and thanks for the ‘”get home tricks”… n1dp… the battery was newly charged …. and seems crew is like you … but they “Blame it on Rio” … that’s way both items been replaced…!!!
  6. Thanks brother for your response; I agree with you about replacement of the battery, and I agree with you that most of the relays on the aircraft are required more than 14v to response; But my Inquiry which may solve the puzzle is:… Which power source energize the Battery Relay, is it the battery only? Or both battery and external power? To make it more clear; we are having an aircraft (out of home station with no maintenance facility) crew reporting that the battery voltage is very low 7v, and Bat.switch failed to connect Bat.with isolated dc bus (which is normal due to low Bat.voltage); and as reported when trying to regain the voltage by recharging the battery with external power the battery failed to build up any voltage during the charge …. So the question is; Is it a battery failure issue only ? or battery relay failure issue preventing the battery from been recharged and subsequently lead to battery failure ? If systematically the Bat Relay is response only to battery voltage; then the possibility of failure is Battery only; but if Bat Rely should response to external power voltage, then Bat Relay is also suspected.
  7. Battery Relay With Battery voltage less than 7 volt; is it possible for the battery to be recharged with external ac power? Systematically… is the “Bat. Relay” can only be energized through a good charged battery..? Or it doesn’t matter; as this relay can also be energized through external power for feeding the “Bat.Bus” as well for recharging the battery. Any feedback will be appreciated as we are having an issue of one of the C-130H.
  8. Hence fuel control units (FCU/TDV) are eliminated, is it possible the defect cause is related to one (or more) acceleration bleed air valve delay in closing (sticky)..? If so, certainly the TIT at the time will be higher than normal until valve/s are forced to close; as for other indication, I am not sure if the fuel will be higher or not (air to fuel ratio); the torque should show somehow less until defective valve/s are closed.
  9. Thanks "Lkuest" for your technical details which help me a lot to have a look at the TD electrical circuits; and by going over the "twisted circuits" it confirmed all the points that you stated in wards. Therefore-in short- can we say… 1- TD valve cannot be locked if TD switch is placed to "lock" below cross-over. 2- Advancing throttle to above cross over while TD switch being locked below cross-over will have no any effect on the TD valve brake.(brake will remain unlocked) 3- Correction light will remain illuminated on the entire throttle range if TD locked below cross-over. 4- The only advantages of locking the TD below cross-over are: a- To arm/energize the "normal limit circuit" on the entire range of throttle. (for TIT not to exceed 1077*). b- To deactivate the BIAS & SLOP corrections.(No fuel trimming at cross-over). Steve1300, I agree with you on the point that TD system is not an effective issue to have the pitch locked; it may only help "if in AUTO" on the case of rpm dropping to below 94% once throttle is retarded while the pitch is locked (over-temp. protection). As for your second point, I understand that you prefer to have the TD locked below cross-over to avoid any value of fuel trim in order to check "uncorrected fuel flow" against fuel governing chart/table.
  10. Lukest, I have been having the same idea on how TD system works as you have it, until I came across the following which mix me up…. Quoting TM 382C-2-3 section 3-page 3: "The other switch "66 degrees coordinator microswitch" is actuated at a throttle lever setting of about 66 degrees and opens a circuit to prevent the temperature datum valve brake from being locked at a throttle lever setting below 66 degrees". Therefore according to the above; the TD brake should not go to lock below cross-over (open circuit) In which my questions arise… what if passing across the 66, while TD switch was already on locked position? Is it going to lock? And if it is supposed to lock; normally it should lock in a position having no any correction/trimming (Null position). As for the correction light, they supposed to remain illuminated hence the system is locked below cross-over. On the other hand, is there any holding circuit (relay) to maintain the lock position on the case of cycling the throttle below and above the 66 switch to prevent the cycling of the TD brake? As for how the system will act if locked? I agree with you and with "pjvr" regarding the existence of over temperature protection.
  11. In two similar cases we found the cause was related to a deteriorated fuel nozzle gasket..
  12. Hi to all members and guests, Looking for an answer to the following... On "fuel governing and pitch lock check procedures" almost all manuals -on hand- are asking to lock the TD; some manuals required to have it "locked" at a governing speed (above cross-over), others asking to lock it once retarding the throttles to below cross-over. The main concept of locking the TD to my understanding is to avoid any sudden change of power when passing through cross-over point.. However which is not clear to me the idea behind locking the TD below cross-over; 1- Is the TD valve going to "Lock" below cross over? Hence the 66 coordinator switch is not actuated yet? 2- How the TD system is behaving once locked below cross-over? 3- How the TD system is behaving once throttles are advanced and passing through the 66 deg….. ? Any highlight on this will be appreciated.
  13. Let us create this scenario to (somehow) explain a defective paralleling valve: Due to valve internal malfunction; Paralleling valve at de-energized condition is not retarded to a full open position. 1- During initial rotation (valve supposed to be fully open) but due to not fully open, the fuel pressure before the 16% rpm will build up but not sufficient to trigger the secondary switch. 2- At 16% the valve will be energized to take a full closed position, this will cause farther increase of fuel pressure causing earlier than normal indication of secondary light. 3- At 65% the valve will be de-energized, thus valve will return to the previous position (not fully open) consequently the pressure will slightly drop causing the light to be off. (You may not see a clear indication of TIT cutback). 4- During flight as fuel temperature will decrease thus fuel pressure will increase and it may reach a point that trigger the secondary switch causing the light to be ON specially during cross feeding the engine from high pressure pumps. Is it a possible scenario ….?
  14. Our defect is solved by changing the NLG actuator, hoping to you the best to solve "the puzzle of the 3 seconds". NATOPS1 I did not catch your point when saying: "If the pin does not retract you will retain the ground and the down indication will remain" As for the LG warning light it was working normally and was not affected by the malfunction of the NLG position indicator. Yes; the point that hesitating us from flying back with the defect is exactly what you have said: "If you fly and retract the gear the next extension may not be "real" and the internal lock may not be engaged". Anyhow thanks to all for the feedback.
  15. Thanks Ramrod for your help and clarification, as for the down lock switch it is LMCO part, and as for switch adjustment we have tried all setting of adjustment, but none of them worked. At present our intention as you state in your post is to replace the NLG actuator, but we are facing some difficulties on doing the task out of home base, we are trying to bring the aircraft under "Exceptional Release" and deal with it at home station.
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