|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : apa|
|Altitude||agl bound lower : 1000|
agl bound upper : 1000
|Controlling Facilities||tower : apa|
|Operator||general aviation : corporate|
|Make Model Name||Helicopter|
|Flight Phase||descent other|
|Function||flight crew : single pilot|
|Qualification||pilot : instrument|
pilot : commercial
pilot : atp
pilot : cfi
|Experience||flight time last 90 days : 100|
flight time total : 6500
flight time type : 350
|Qualification||other other : other|
|Anomaly||aircraft equipment problem : critical|
|Independent Detector||other other : unspecified cockpit|
|Resolutory Action||flight crew : declared emergency|
flight crew : overcame equipment problem
flight crew : regained aircraft control
|Air Traffic Incident||other|
Took off for 1 trip around traffic pattern to test collective pitch rigging. Preflight control checks were normal, hover check and takeoff were normal. On downwind cyclic control stick became locked at the center position and only minimal cyclic movement was possible. Other controls were normal. Autoplt failure and hydraulic failure procedure had no effect. Friction was adjusted to full loose west/O effect. I declared an emergency at the point where an uncommanded left turn was taking the aircraft into the pattern of other airport traffic. Oscillating the cyclic rapidly fore and aft and side to side eventually returned full boosted control and an uneventful landing was made. Probable cause was failure by maintenance crew to remove a cyclic centering pin that was being used during aircraft rigging prior to the flight. I was unaware such a pin existed, let alone had been installed. To compound the problem the t-handle on the pin had been taped to the bottom of the aircraft to prevent it from falling out during rigging. As a corrective action I would advise that one person have responsibility for installing and removing this pin, that a 'remove before flight' streamer be attached to it, and that the pin not be taped so it will fall free if all else fails.
Original NASA ASRS Text
Title: ON TEST FLT OF HELICOPTER AFTER MAINTENANCE, CYCLIC BECAME LOCKED WITH ONLY MINIMAL MOVEMENT. PLT MADE SUCCESSFUL LNDG.
Narrative: TOOK OFF FOR 1 TRIP AROUND TFC PATTERN TO TEST COLLECTIVE PITCH RIGGING. PREFLT CTL CHKS WERE NORMAL, HOVER CHK AND TKOF WERE NORMAL. ON DOWNWIND CYCLIC CTL STICK BECAME LOCKED AT THE CTR POS AND ONLY MINIMAL CYCLIC MOVEMENT WAS POSSIBLE. OTHER CTLS WERE NORMAL. AUTOPLT FAILURE AND HYD FAILURE PROC HAD NO EFFECT. FRICTION WAS ADJUSTED TO FULL LOOSE W/O EFFECT. I DECLARED AN EMER AT THE POINT WHERE AN UNCOMMANDED L TURN WAS TAKING THE ACFT INTO THE PATTERN OF OTHER ARPT TFC. OSCILLATING THE CYCLIC RAPIDLY FORE AND AFT AND SIDE TO SIDE EVENTUALLY RETURNED FULL BOOSTED CTL AND AN UNEVENTFUL LNDG WAS MADE. PROBABLE CAUSE WAS FAILURE BY MAINT CREW TO REMOVE A CYCLIC CENTERING PIN THAT WAS BEING USED DURING ACFT RIGGING PRIOR TO THE FLT. I WAS UNAWARE SUCH A PIN EXISTED, LET ALONE HAD BEEN INSTALLED. TO COMPOUND THE PROB THE T-HANDLE ON THE PIN HAD BEEN TAPED TO THE BOTTOM OF THE ACFT TO PREVENT IT FROM FALLING OUT DURING RIGGING. AS A CORRECTIVE ACTION I WOULD ADVISE THAT ONE PERSON HAVE RESPONSIBILITY FOR INSTALLING AND REMOVING THIS PIN, THAT A 'REMOVE BEFORE FLT' STREAMER BE ATTACHED TO IT, AND THAT THE PIN NOT BE TAPED SO IT WILL FALL FREE IF ALL ELSE FAILS.
Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.