737NG aileron control wheel stiff in roll axis

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737NG aileron control wheel stiff in roll axis

Postby banwar » 04 Jul 2018, 06:14

HI, ONE OF OUR 737-800 (WINGLETS), OPERATES DAILY TO THE DESERT. DURING LAST 12 MONTHS WE HAVE RECEIVED MANY PILOT REPORTS RELATED TO HEAVY CONTROL WHEEL FORCES IN ROLL AXIS, SUCH AS :
1) AILERON CONTROL WHEEL STIFFNESS, ESPECIALLY AT FULL RANGE TRAVEL
2) SPEEDBRAKE HANDLE STIFFNESS.
3) AILERON INPUTS ARE VERY HARD WITHOUT AUTO PILOT. DIFFERENCE IN AILERON TRIM UNIT IS ONE.
4) AILERON TRIM DISPLACED 1 UNIT TO THE RIGHT ON F/O CONTROL COLUMN WITHIN CAPT INDICATES ZERO CENTER.
5) FLT CONTROL STIFFNESS PERSISTS IN ROLL AXIS AND SPEED BRAKE HANDLE TO FLT DETENT.

NOTE: CAM FOLLOWER BEARING REPLACED AUG 2017, DEFECT PERSIST. SPOILER MIXER AND RATIO CHANGER REPLACED OCT 2017, DEFECT PERSIST.

6) LATEST REPORT 3 JULY 2018 AND TROUBLESHOOTING AS BELOW:
DURING PRE-FLIGHT CHK, FLIGHT CONTROLS NOTED TO BE STIFF IN THE ROLL AXIS WITH HYD SYS PRESSURIZED.
AILERON CENTERING MECHANISM CENTERING SPRING ADJUSTED, FORCE TEST C/OUT SATIS. DURING PREFLIGHT CHKS,
FOLLOWING WAS NOTED, AFTER HYD SYS PRESSUIRZED, CAPT FLIGHT CONTROL POSITION CENTERED/ F/O FLIGHT
CONTROL 1 DEGREE OFFSET. T/SHOOTING C/OUT BODY CABLE AA & AB FOUND SATIS. ROLL FORCE TRANSDUCER WIRE
BUNDLE CHECKED IF TOO TIGHT FOUND SATIS. AILERON TRANSFER MECHANISM INSPECTED FOR EXCESSIVE FRICTION.
FOUND SATIS. CONTROL COLUMN U JOINT & SUPPORT BEARING INSPECTED FOUND SATIS. TENSION CHECKED ON CABLES
ABSA & ABSB. FOUND SATIS, SAME ABOVE CABLES INSPECTED FOR CONDITION & BLOCKAGE. ALL FOUND SATIS. LEFT
AILERON DEFLECTED DOWN WHILE RIGHT IS FLUSH WITH HYD SYS PRESSURIZED. RIGHT WING SPOILER PANELS 8/9/10/11
DEFLECTED.

ANY RECOMMENDATIONS ARE APPRECIATED.
BRGDS
banwar
 
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Joined: 17 Jun 2009, 07:19

Re: 737NG aileron control wheel stiff in roll axis

Postby Dunny » 04 Jul 2018, 15:05

I was going to say spoiler mixer, but it appears you've already replaced that...
Dunny
 
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Joined: 17 Feb 2007, 20:56

Re: 737NG aileron control wheel stiff in roll axis

Postby sjap » 09 Jul 2018, 13:33

Maybe the vertical input axis bearings in the weheel well are contaminated with sand? of corroded?
See similar complaint at:
http://www.sjap.nl/temporary-solution-for-heavy-aileron-input-forces-737-all/
sjap
 
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Location: Netherlands

Re: 737NG aileron control wheel stiff in roll axis

Postby Nug » 11 Jul 2018, 15:11

I would start with attaching a straight edge across the control wheels and making sure all for contact points touch with verifying the trim pin fits free. . Address this first. A couple things to try check if A/S-4 fits in the Xmas tree with hyd on, use flight control hyd switches turning them off and on individually and checking A/S-4 .Could be pcu’s fighting. Do the pogo adjustment check. If that’s all good your ailerons should be in the neutral rigged position. If they are and the spoilers are still up make sure all the wheel rig pins fit free. The only way for the spoilers to be deflected at this point is thru the ratio changer input .Do the ratio changer input rod adjustment check .If that’s good remove the spring cartridge turn on hyd and see if the spoilers stow.This could be a bad spring cartridge. As far as the stiff speed brake lever. It could be an electric actuator going bad. Any reports of auto speed brake inop? Or the fwd speed brake mechanism going bad. I would address the to symptoms separately. Good luck
Nug
 
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Re: 737NG aileron control wheel stiff in roll axis

Postby banwar » 15 Jul 2018, 12:57

Thanks all. We replaced the aileron power lower control assembly P/N 251A1661-13. The lower spacer P/N 69-41223-2 in this assembly was also found cracked. So far no further pilot complaints.
much appreciated.
regards
banwar
 
Posts: 27
Joined: 17 Jun 2009, 07:19


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