airman57 Posted April 27, 2011 Share Posted April 27, 2011 ''DURING AIRCRAFT DECENT (LANDING) (FIRST OF ALL) ENGINE 4# FUEL FLOW,TIT AND TORQUE SUDDENLY INCREASE,(THEN) RPM IMMEDIATELY DROP%80 WHILE THROTTLE AT FLIGHT IDLE.(BELOW XOVER) FLIGHT CREW SHUT THE ENGINE AT %80 RPM'' (EMERGENCY) NOTE: Flight crew said that no change temp.datum valve switch in null position. WE CHECKED THE ENGINE: 1.Operational Checkout of Throttle Control System------------------------------ (no problem) 2.Operational Checkout of Engine Condition Control System---------------- (no problem) 3.Operational Checkout of Propeller - Static Condition---------------------------(no problem) 4.Inspection of Engine Power Section (with baroscope)------------------------ (no problem) 5.Power section and Reduction gear box mag.plug check----------------------(no problem) 6.Electrical Components Check Using Electrical Components Checkout Test Set----------(no problem) 7.Check of Temperature Datum Control System With Engine Static UsingTest Set--------(no problem) 8.We run the engines for run-up control--------------------------------------------------(no problem,all of indications were normal.) WE DECIDED TO CHANGE THE FOLLOWING PARTS AND WE CHANGED. 1.Valve Housing 2.Main Fuel Control 3.Fuel Enrichment Valve (THEN AGAIN) (AFTER CHANGED THE PARTS) WE RUN THE ENGINE FOR CONTROL.(NO PROBLEM) WE DECIDED TO FLY THE AIRCRAFT (TO CONTROL FLIGHT) AND AFTER TAKE OFF WHILE CLIMBING. (APPROXIMATELY AFTER 7-8 MINUTES) SAME PROBLEM WAS OCCUR IN FLIGHT AFTER NTS CHECK WHILE ADVANCE THROTTLE FROM FLIGHT IDLE TO XOVER POINT.(APPROXIMATELY ABOVE 1 INCH OF FLIGHT IDLE DETENT) NOTE:FLIGHT CREW SAID THAT NTS CHECK WAS SUCCESS IN FLIGHT.BUT...(TWO TIMES EMERGENCY) ANYONE CAN GIVE SOLUTION. Quote Link to comment Share on other sites More sharing options...
airman57 Posted April 27, 2011 Author Share Posted April 27, 2011 (Approx.value) ENGINE NO.1 ENGINE NO.2 ENGINE NO.3 ENGINE NO.4 TORQUE 1000 IN.LB. 1000 IN.LB. 1000 IN.LB. 15.000 IN.LB. TIT 550 C 550 C 550 C 1060 C FUEL FLOW 600 PPH 600 PPH 600 PPH 2400 PPH (AT 4000') and RPM DROPED %80 Quote Link to comment Share on other sites More sharing options...
DanGothe Posted April 28, 2011 Share Posted April 28, 2011 Just a shot in the dark even though you did the yellow box test have you ohmed out the co-ordinator ? and The J-2 Lead even though you check it while yellow boxing .Maybe disconnect it and ohms ck it out maybe there is a break or some wiring issues in the wing Quote Link to comment Share on other sites More sharing options...
tenten Posted April 28, 2011 Share Posted April 28, 2011 Second shot in the dark. “To my knowledge no engine component can misbehave and lead to such…. except two: 1- FCU. 2- TD system (if in auto regardless of throttle position). Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted April 29, 2011 Share Posted April 29, 2011 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 Quote Link to comment Share on other sites More sharing options...
airman57 Posted May 1, 2011 Author Share Posted May 1, 2011 It looks like the fuel system problem (in my opinion) But why did RPM drop? (under %80 RPM......) Engine was go from %100 RPM to %80 RPM in flight.then flight crew shut down the engine. (When failure occure) Engine values firstly indicate torque :15.000, tıt:1050 C , fuel flow :2400 pph.After this situation RPM should not drop when the engine fuel flow,tıt,torque increase. (because engine's power is very high) (I don't understand this situation.) I NEED MORE TECNICAL INFORMATION FOR THIS FAILURE.THANK YOU pjvr99,tenten,DanGothe, Quote Link to comment Share on other sites More sharing options...
DanGothe Posted May 4, 2011 Share Posted May 4, 2011 anytime I can be of assistance . Quote Link to comment Share on other sites More sharing options...
keepemflying130 Posted May 5, 2011 Share Posted May 5, 2011 Problem has to be multiple component and/or wiring. This rig is not airworthy. Take it off the wing. Throwing parts at it, and cannot duplicate on ground with that kind of discrepancy is, in my mind, grounds for R2. Probably cheaper, and surely quicker in the long run. Sending up "I hope its not another IFE" is not in my mind acceptable. Quote Link to comment Share on other sites More sharing options...
tenten Posted May 5, 2011 Share Posted May 5, 2011 To my opinion you might have an issue of TD system malfunction accompanied with play on the pump housing due to warn out/looseness of anti-rotation bracket. (Sudden increase of power twists the pump housing…. activating the NTS system …….. leading the RPM to drop.) But again the value of power increase appeared to me beyond the ability of TD malfunction to produce, unless I am wrong on this understanding. Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted May 6, 2011 Share Posted May 6, 2011 Couple of things still have me puzzled: in the first post was stated problem occurred during descent. That would mean a pretty serious yaw when then miscreant engine suddenly increased power. The second thing that worries me is the 80% - bleed valves would have opened, and flameout would be the result This is really wacky ............. Quote Link to comment Share on other sites More sharing options...
Lkuest Posted May 6, 2011 Share Posted May 6, 2011 I wish I had my hands on that plane so I could poke around, but my shoot-from-the-hip instinct says it's a propeller malfunction. If the propeller causes the RPM to drop, the fuel control will think it's still trying to accelerate up to ground idle RPM, and start putting a lot of fuel. We've had at least three cases that I can think of on the top of my head where the Valve Housing caused the engine to go to full takeoff power (fuel flow, TIT, torque all went up) upon upspeeding the engine. The bleed valves opening up below 94% could also partially explain the high TIT without massively overtorquing. Again, this is shooting from the hip, so I make no claims that I know exactly what's going on. I'm just saying that I wouldn't be suprised one bit if a prop change fixed the problem. Quote Link to comment Share on other sites More sharing options...
tusker Posted May 10, 2011 Share Posted May 10, 2011 ............good day guys!!!!!!!!.............but!!.........if something increases fuel!!!............you're gonna get an increase of TIT and Torque!!! " The bleed valves opening up below 94% could also partially explain the high TIT without massively overtorquing." ......yes but!!!......what about the fuel flow increase!!!! FCU or TD system!!!.................maybe!!!!!!!!!!!! How's the hardware in the system!!...........For sure............something is increasing fluel flow!...............Well!!! let's keep on thinkin' about it!! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.