tenten

Copied, checking…..Thanks Tiny ..but .. Been broken out is authority of change..?? What about Job Guide, balancing…??

Welcome back to your brothers and your site.

Prop guys, need your help on this. “Beyond Repair†prop Hub Mounting Bulkhead Assembly. (Part No. 554636) Is it a replaceable item? If so, is the prop required any balancing after the replacement? Info, and reference will be appreciated.

LKUEST, thanks for the information regarding that; Malfunction of a valve housing may cause high fuel flow problems. If correct…., this might be one of the "missing chains" that will help in explaining most of the issue. Thanks Pjvr99, the valve housing was confirmed at fault: regarding the other possibilities you mentioned (synchrophaser, bad tachometer generator, and the pulse generator) according to my understanding they are “out†upon shifting the prop to mechanical gov, which was done and failed to alleviate the defect. NATOPS1, thanks for the input regarding the possibility of a defective Coordinator; But….to my understanding failure of this component can be either electrical failure (potentiometer) or mechanical failure; The electrical failure should be isolated by shifting the TD to null, which was done with no effect; While the mechanical failure should be detected during the static check of blade angles and throttle rigging, which was also not detected. Quoting LKUEST: You may have two different problems, but I believe the Valve Housing is at least partly at fault. I agree 100% with what you are saying, and in fact it is approved that the defect is related to more than one component, and one of the most is the Valve Housing. Quoting LKUEST: The easiest way to troubleshoot a problem with multiple likely culprits is to fix one problem at a time, the most obvious cause, and see what other problems are left. The valve housing might fix everything. Well, unfortunately –according to the first engine reading- we started the task with changing the FCU based on the assumption that; No component having the ability to misbehave with fuel -to the point of having 500 lb of fuel more than a normal engine- with TD NULL- accept the “FCUâ€. The second point in pushing us to start with the FCU is the oil leakage (from drain mast) which was well beyond the static limit (and it was confirmed coming from FCU not the fuel pump (checked at the TEE joint of the two lines). So as we changed the FCU and C/Out the RUN the defect remained as it was on the last…..high RPM (103%) with extremely low fuel, this defect remained constant during multi-starts and open power, therefore the next to "get down" was the Valve Housing….. Done…And the result was ….Engine power and RPM returned to normal.. Except…... The NULL start was low 730⁰C with no correction at x-over and the TD system failed to respond during temperature controlling check. Therefore and after failure to increase the null start TIT from null orifice ….The third component (TD VALVE) was clearly asking to follow the others ……Done.……. All Defects Cleared. Brothers, as you noticed we changed THREE components to clear the defect, two components out of the three I certainly having no doubt of their defectiveness (valve housing and TD valve) the one that I am not sure about it -regardless of oil leakage- is “The FCUâ€, if not at fault during high RPM (103%) and it’s only doing its over-speed protection by cutting fuel, what about the first reading low RPM (96%) with high fuel. Or is it possible for a defective TD valve to act intermittently during open power only while TD in NULL and “Dump In†the bypassed fuel? ……. Hard to swallow. Or is it as LKUEST mentioned; Malfunction of a valve housing may cause high fuel flow..???

Once upon a time; While initiating cruising speed at level 220 engine no.1 rpm started dropping to 97%, shifting to mechanical governing the rpm further dropped to 96%. In flight pitchlock check procedure carried out as stated on section 3 of dash one, by moving the affected engine throttle “forward†while maintaining constant TAS, the result was no increase of RPM and no change of power (fuel,TIT, and torque) the pilot elect to shutdown the effected engine. After three engine safe landing, the effected engine statically checked …… the only abnormality was “oil “ dripping from fuel control drain line!!!!! In ground check during the start, the effected engine was coming to normal speed as a normal engine, but when moving the throttle from flight idle toward cross-over….. the fuel accompanied by TIT and torque started gradual abnormal increase while the RPM remain as it was (96%) the reading of the effected engine at just below cross-over was: RPM 96% TIT 1000⁰C With 500 lb more fuel than other symmetrical engine. The above reading was neither affected by shifting TD to NULL, nor shifting prop to mechanical. Engine was shut-down to “recheck†throttle rigging… Rigging only checked..found “SATâ€. On the second start and upon moving the throttle from flight idle toward cross-over the effected engine started behaving in a deferent manner….. RPM started gradual increasing and hit the 103% with extremely low fuel,TIT and torque. Reading of the effected engine at just below cross-over was: RPM 103% TIT 720⁰C Fuel flow 1100 lb TP 4100 in/lb The above reading was also neither affected by shifting TD to NULL, nor shifting prop to mechanical governing. One more point… in both cases crossing the cross-over point had no any corrections..!!! Guys of herkybirds; Is there any explanation to what’s going on.. :confused:.. And which one of the “three†should we go for….???

Great effort for a great site, thanks a lot Casey.

Well….., the 100% is beyond legal authority of bad guys. It is a self desired of the “Mighty Hercâ€. So, … “Keep an eye on the leverâ€. ;)

Yes, larry... In your days the “Run†was with flaps up. So… it is a matter of distributing the load, 30 years “hitting†tail, and… 30 years “hitting†flaps;……. fair and logic. Note: (we may use the correct word…… other than “hittingâ€â€¦.. “Casey is busy with the website†;)

Hi, slickum17 If my memory is correct: The 50% is to relieve stresses imposed on the tail section of the airplane during the Engine Runs. I Read it somewhere, and I will try to find and post the reference.

As I promised to post the finding: “The Good news†is: Aircraft now -out base- and is accomplished more than 5 sorties with no defect reported of Radio Altimeter. “The Bad†is the cause of defect which is slightly “hazyâ€; due to been “pushed†to change two components at the same time. -The R/T (which had been changed before 2 times with no effect). -And the Receiver Antenna. Why changing the R/T for the third time …!? What about the other two R/Ts .....?!! in which one of them is taken from a serviceable aircraft and fail to clear the defect. I have no answer, but certainly “Radio Shop†and some “avionic guys†having the answer….. I surely believe that the Receiver Antenna is the “culprit†Anyhow……, Thanks to all for the help.

As (NATOPS1) said; “Just between you and me... and all the other Herkybird membersâ€.... Do not go for valve housings ($$$) to solve a momentarily flickering of “GEN OUT†to satisfy guys of “one second throttles movementâ€. Use “The 4 seconds movement reference to save the XX,000 $ X3 Yes you may go for “Prop filters†and “Synchrophaser box†-As brothers advise you. You may also go for:- -Prop hydraulic level checks.(low level leading to lag response) -Low Pitch stop setting if at high setting. (High setting will cause low RPM setting when retarding throttles to F/Idle) -Throttle to fuel control linkage adjustment for adding some fuel.(more fuel more RPM at F/Idle) In general just improve valve housing response or increase RPM at F/idle position(to avoid the second "hit" beside the one at cross-over). …..might help. By the way, are you using the same type valve housing on all the four engines (same part numbers)? The things that still spin on my head with no answers: 1- If the illumination of Gen.Out lights are due to the drop in RPM/frequency it should accompanied with momentarily shifting of load to (No. 3 Generator) in which at the moment will take only the Ess. and Main AC buses (can be noticed by the increase of No.3 load meter during the illumination of the three OUT lights); therefore the “Bus Off†lights of LH & RH should come “Onâ€/or at least flickers momentarily at that time. 2- The dimming & brightening of thunder storm /dome lights which are powered by main Dc through TRUs through Main Ac bus (No.3 generator) is indication of two possibilities either momentarily heavy load imposed on No.3 generator (left alone to take the load of two Buses) or the cycling of Bus contactors transferring load from one to another and in both possibilities the “Bus Off†lights of LH & RH should also come “On†Why not any “Bus Off†light comes “On†or flickers…..!!??

Brothers of “FAST WARDS†(cnd) (we did not carry a C/C.) (ops) (gen) (w/ temp datom) (It is almost w/o fail) (BTW) (VDs flickering) (and f/d and c/c thunderstorm lights dimming and brightening) (Tnx.) (AFAIK)………… The last one I thought it is a new avionic components and I spent a couple of hours digging net and books till I got it. Non standard abbreviations on a technical issue lead me and others to misunderstand. Apologize for me and others for the misunderstanding. Back to the subject, Pulling back the throttles “fast†from 1077⁰C to flight/idle according to my knowledge may affect the engine (RPM/ FREQUENCY) and cause it to drop below the limit on the present of one or more of the following factors: 1-TD system (high correction at cross-over) 2-Low pitch stop setting (high setting leads RPM to drop/frequency to drop). 3-FCU response not compensating to fast movement of throttles. 4-Propeller governor control response to fast movement of throttles. 5-Throttle to fuel control linkage miss-rigged (low). One or more from the above may momentarily leads RPM/FREQUENCY to drop and cross the threshold (365) of generator out light, ….but three engines having the same sickness….!!! On the other hand a high load on (Ess AC Bus) accompanied by one of the above mentioned may also leads the generators to be “out†momentarily (in sequence of bus shifting) due to the high load at a moment of generator weakness- voltage/RPM- till generators recover voltage/RPM drop. For the limit of how fast moving the throttles some maintenance T.O. stated that the foreword movement should not be less than 4 seconds, but for the “high ranks†the 400% discount dropped it to only one second (maybe for emergency only). For the point that the lights are not coming “On†when power pulled from 1010⁰C, I couldn’t explain it technically. Maybe the third law of Newton…..as he stated: (Hitting the ground from second floor is worse than from first) Maybe “ten ten†is a safe figure…… nobody knows.

Hi, Abnormal electrical high load imposed on generators at a moment of weakness leading them-in sequence of bus shifting-to momentarily get-out then recovered. 1- Check for abnormal load on generators especially on (No.2). 2- Check also TRUs for high load. 3- If high load is present check the cause. 4- Reduce the load to the minimum and recheck. 5- Switch off one generator at a time and recheck. (If equipped use the APU gen. to take ESS.AC and recheck) 6- Swap voltage regulators and recheck. (No.3 with No 2) 7- Switch to “null” TD control one at a time and recheck. Hope the above will help you moving closer to the defect.

Hi Tref, Have you changed Auto De-icing relay? If not, give a try, I am saying that based on system electrical circuit.

By the way, is anybody remember above what cabin altitude the flying crew required to be on oxygen. Our “SOP†–if memory not against me- state:- 8,000 night time. 10,000 day time, and maybe it is limited to certain time. Table attached showing cabin altitude in relation to aircraft altitude when deferential pressure at normal maximum (15.18) Hg.

Thanks Tiny, Connectors will be checked carefully, I am also request “TDRâ€/“VSWR†kit, they promised to provide. I will post the finding.

M wales, What was the cabin altitude at that time?!!! :cool:

Good day, I have got the feedback. Defect improved a bit, but still acting and not accepted. Now -according to flying crew report -defect shows as only momentarily cycling of the Radio Altimeter Indicator from time to time, the cycling starts in the altitude of approximately 500 feet AGL to 10,000 feet; above the 10,000 feet the indicator will stop cycling and behave as normal. NO steady warning FLAG reported; and NO effect to other systems during the cycling. I am still out of test kit; my intention upon aircraft arrival is to focus on both RF cables; and to change the receiver antenna. The possibility of other system interference(GPWS,TCAS,FCF-105) causing the radio altimeter to fail is also knocking my head, but…...... Any other idea or technique to spot the defect will be appreciated.

Teny, NATOPS1, thanks for the response and the advice which help me on the last corrective action. Larry myers, thanks for pushing the “TOP†guys to react. Apologize been late (Time dif. 8hrs ahead, weekend Friday & Saturday on my universe). The “CAN DO†& “THE BIRD†simply I was referring to the airplane the “mighty Hercules†not the component nor the system, so apologize for that, I shouldn’t use those terms on technical issues. For clarification of the defect, during the last FCF I was inboard with the flying crew, before rolling to T/off all the functional test of radio altimeter and the other related system (TCAS, GPWS) was as advertised… “OKâ€. At initial climb the Radio Altimeter was reading smoothly, once the aircraft reached approximately the 300 feet AGL the warning flag of the Radio Altimeter comes in view followed by illumination of GPWS inoperative light, followed by “TCAS failed†on the MFD indicator, this condition remain during the climb and the cruise at 10,000 feet. During the landing phase (it was ILS Coupled Approach) the captain advised that some of the inputs such as (raising runway, decision height, GS deviation signal and capture point) will or might not be available or reliable spicily during the last phase of ILS landing due to the malfunction of the Radio Altimeter. Anyhow at approximately the 300 feet from touchdown the Radio Altimeter becomes a life, the FLAG disappeared and all the previous warning ended. The same scenario repeated twice. Last finding and action taken is:- 1- One of the RF connectors points on the R/T mount receptacle (the one receiving the input from receiver antenna cable) found deteriorated (50% of contact wall found missing). Mount changed with new one. 2- Transmitter antenna changed with new one. 3- Due to operation requirement aircraft released today (Out Mission) without FCF, I am expecting a call from flying crew of the result, and once I get it, sure it will be posted. As for general knowledge, of the AL-101 Low Range Altimeter, the normal system operation is to provide accurate terrain clearance between 0 and 2,500 feet, the indicator equipped with test switch, MDA set knob, minimum decision altitude light, inoperative red flag, and a mask at the end of the indicator scale. The Radio Altimeter has three basic mode of operation: Mode 1- Aircraft below 2,500 feet, normal return signal and no malfunctions detected. The flag is out of view and the indicator indicates the proper altitude. Mode 2- Aircraft above 2,500 feet, and signal returns are normal. The flag is out of view and the indicator pointer is behind the pointer mask. Mode 3- System functional test (manual) the flag is in view and the pointer indicates 100 feet. As for system interface with other systems the radio altimeter interfaces with: 1-The FCS-105:- Inputs from Radio Altimeter used to desensitize the Glide Slope, controls the runway raising symbol (the raising up of the symbol starts from 200 feet to touchdown during ILS landing mode) and the decision height (DH) light on the ADI during approach to landing. Therefore it is not affecting the whole FCS-105 systems, auto-pilot and other mode of the system can be used during the malfunction of the Radio Altimeter. 2-GPWS:-The R/T provides altitude and flag alarm to the GPWS system, while the radio alt. indicator provides MDA to the GPWS, therefore almost the whole GPWS system depends on Radio Altimeter, in which GPWS inoperative warning light will come ON if Radio Altimeter malfunction. 3-TCAS:-Altitude received from Radio Altimeter is used by TCAS to determine distance to the surface (In order to inhibit or enable some modes of operation in relations to distance from ground level. I hope this lengthy shallow information guides you to help me. Thanks again for all of you.

Avionics/radio & radar guys, have you experience this defect before? C-130H, equipped with radio low range altimeter AL-101 (interfaces with GPWS, FCS-105, and TCAS) Whenever the “CAN DO†hits the 300 AGL the “OFF FLAG†of Radio Alt. appears accompanied with failure of the other related system mentioned above. Yet, unfortunately I am out of proper test equipment. Voltage and continuity checks, done. Doesn’t show any abnormality. Radio Alt. R/T changed. Radio alt. indicator changed. Still the bird behaving the same, above 300 feet flag “ON†below 300 feet back to normal operation. Can I go for the antennas, and which one? Any suggestions to this problem will be appreciated, since the next will be the 3rd FCF:confused:.

What’s up by me!!!!.... “Non senseâ€. Memory alone misleading. (TSN Exceed 464,000,000)hrs. Apologize. Back to the books. Yet book troubleshooting leads only to: 1- ATM Generator Control Panel (GCP). 2- ATM Generator Contactor. Since both had been changed.We should look for the unusual……. (Defective Wiring)

If the circuit is identical with H model (for the light to remain “off†needs 28v to be delivered from FSR to the GCP) therefore you may have: 1-FSR malfunction. 2-Continuity between FSR and GCP is broken.

Best wishes, FLYBOY773 But, don’t be late to find a civil herk, for I am reading behind the words.â€You start climbing without “Oxâ€

Jetcal1, pjvr99. Thanks a lot for your clarification inputs to my issue. Unfortunately, an FCU and TD valve unit had been changed within the last two months for only solenoids malfunction. Therefore I am trying to convince -those supply folks and above-, out of sending the whole units for repair, there is -“In Another Universeâ€- those simply items can be changed/repaired under whatever Coordination approval from contractor -(SMR code change request / Item coding request/ whatever)- “Their Headache†Anyhow. “We scramble to find some comfortable ground. -In the Gap Between Right and Wrong-“ Thanks again brothers.

It is what I am looking for, appreciate your help bischoffm. So it is changeable and repairable.