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Partial control capability with a jammed cyclic in an AS350 rotary winged aircraft creates the need for a different approach landing procedure during cold WX operations near W12, wa.
| Attributes | |
| ACN | 540975 |
| Time | |
| Date | 200202 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| State Reference | WA |
| Altitude | agl single value : 1500 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Snow |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | AS 350 Astar/Ecureuil |
| Operating Under FAR Part | Part 135 |
| Flight Phase | climbout : initial |
| Flight Plan | None |
| Person 1 | |
| Function | flight crew : single pilot |
| Qualification | pilot : multi engine pilot : commercial pilot : cfi pilot : atp pilot : instrument |
| Experience | flight time last 90 days : 80 flight time total : 14000 flight time type : 700 |
| ASRS Report | 540975 |
| Person 2 | |
| Function | observation : passenger |
| Events | |
| Anomaly | aircraft equipment problem : critical ground encounters other other anomaly other anomaly other anomaly other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | aircraft : equipment problem dissipated flight crew : exited adverse environment |
| Consequence | other other |
| Supplementary | |
| Problem Areas | Environmental Factor Flight Crew Human Performance Aircraft |
| Primary Problem | Aircraft |
Narrative:
Landed on ridge side of cornice with bear paws on skids allowing nose to sink in deep new snow. Skiers checked avalanche hazard and skied to bottom pick-up (about 30 mins). At takeoff, could not move cyclic (aircraft rotor pitch control) forward. Felt like solid control lock. Collective pitch (blade pitch control) gave limited control of pitch attitude of helicopter so I headed for lost river airstrip to attempt run on landing. After 10 mins, the lock disappeared and I was able to land normally. Maintenance changed fore and aft servo (mixing units) to be sure but my theory may have merit, ie: landing warm a-star in deep snow with nose way down allowed snow to slide into belly pan and begin to melt. Shutting down allowed snow to refreeze where it interfered with bell crank, control linkage or whatever. Flying toward airstrip allowed aircraft to warm, melted ice/snow which dropped out of harms way. While bear paws have lots of fans, this may be an argument for full length skies. Otherwise, be aware of snow getting into belly pan and launch carefully. Chief pilot handed report to NTSB.
Original NASA ASRS Text
Title: PARTIAL CTL CAPABILITY WITH A JAMMED CYCLIC IN AN AS350 ROTARY WINGED ACFT CREATES THE NEED FOR A DIFFERENT APCH LNDG PROC DURING COLD WX OPS NEAR W12, WA.
Narrative: LANDED ON RIDGE SIDE OF CORNICE WITH BEAR PAWS ON SKIDS ALLOWING NOSE TO SINK IN DEEP NEW SNOW. SKIERS CHKED AVALANCHE HAZARD AND SKIED TO BOTTOM PICK-UP (ABOUT 30 MINS). AT TKOF, COULD NOT MOVE CYCLIC (ACFT ROTOR PITCH CTL) FORWARD. FELT LIKE SOLID CTL LOCK. COLLECTIVE PITCH (BLADE PITCH CTL) GAVE LIMITED CTL OF PITCH ATTITUDE OF HELI SO I HEADED FOR LOST RIVER AIRSTRIP TO ATTEMPT RUN ON LNDG. AFTER 10 MINS, THE LOCK DISAPPEARED AND I WAS ABLE TO LAND NORMALLY. MAINT CHANGED FORE AND AFT SERVO (MIXING UNITS) TO BE SURE BUT MY THEORY MAY HAVE MERIT, IE: LNDG WARM A-STAR IN DEEP SNOW WITH NOSE WAY DOWN ALLOWED SNOW TO SLIDE INTO BELLY PAN AND BEGIN TO MELT. SHUTTING DOWN ALLOWED SNOW TO REFREEZE WHERE IT INTERFERED WITH BELL CRANK, CTL LINKAGE OR WHATEVER. FLYING TOWARD AIRSTRIP ALLOWED ACFT TO WARM, MELTED ICE/SNOW WHICH DROPPED OUT OF HARMS WAY. WHILE BEAR PAWS HAVE LOTS OF FANS, THIS MAY BE AN ARGUMENT FOR FULL LENGTH SKIES. OTHERWISE, BE AWARE OF SNOW GETTING INTO BELLY PAN AND LAUNCH CAREFULLY. CHIEF PLT HANDED RPT TO NTSB.
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.