ASN Wikibase Occurrence # 39501
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| Date: | Tuesday 24 May 1994 |
| Time: | 14:29 LT |
| Type: |  Thorp T-18C |
| Owner/operator: | Praker, Robert M. |
| Registration: | N86BP |
| MSN: | 1386 |
| Total airframe hrs: | 1 hours |
| Engine model: | Lycoming O-360-A4M |
| Fatalities: | Fatalities: 1 / Occupants: 1 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | Phoenix, AZ -
 United States of America
|
| Phase: | Initial climb |
| Nature: | Unknown |
| Departure airport: | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
AFTER THE FIRST TEST FLIGHT FOR THE HOME BUILT AIRPLANE, THE TEST PILOT TOLD THE OWNER/BUILDER THAT HE HAD TO HOLD 35 POUNDS OF FORWARD STICK PRESSURE TO MAINTAIN LEVEL FLIGHT IN CRUISE. THE BUILDER AND TEST PILOT REMOVED THE STABILATOR ANTI-SERVO TAB CONTROL ARMS AND BENT THEM IN A VICE WITH A MALLET. THE ARMS WERE SUBSEQUENTLY REINSTALLED AND THE AIRPLANE TOOK OFF ON A SECOND TEST FLIGHT. VIDEO TAPE SHOWED THE SECOND TAKEOFF INITIAL CLIMB TO BE STEEPER THAN THE FIRST. SHORTLY AFTER TAKEOFF, THE TOWER ASKED THE PILOT WHY HE WAS TURNING RIGHT INSTEAD OF THE REQUIRED LEFT TURN. HE STATED 'I GOT PROBLEMS HERE.' THE AIRPLANE CONTINUED TO CLIMB AND WAS SEEN TO ENTER A RIGHT SPIN FROM A NOSE HIGH, STEEP RIGHT BANK ATTITUDE. THE TEST PILOT HAD SEVERAL YEARS TEST EXPERIENCE AND 1,000 HOURS IN THE ACCIDENT MAKE AND MODEL. THE REASON FOR THE STABILATOR CONTROL MALFUNCTION WAS NOT DETERMINED. HOWEVER, A MAINTENANCE INSTRUCTION ADJUSTMENT RIGGING CHECK WAS NOT PERFORMED AFTER THE REINSTALLATION OF THE ARMS.
Probable Cause: THE PILOT'S INABILITY TO PREVENT AN INADVERTENT STALL AND HIS INABILITY TO RECOVER DUE TO A RESTRICTION IN THE MOVEMENT OF THE STABILATOR FOR UNDETERMINED REASONS. A FACTOR WAS THE FAILURE OF THE OWNER/BUILDER AND THE PILOT TO ACCOMPLISH A CONTROL RIGGING CHECK PRIOR TO THE FLIGHT.
Accident investigation:
 |
|
Sources:
NTSB FTW94FA176
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 24-Oct-2008 10:30 | ASN archive | Added |
| 21-Dec-2016 19:23 | ASN Update Bot | Updated [Time, Damage, Category, Investigating agency] |
| 10-Apr-2024 07:16 | ASN Update Bot | Updated [Time, Operator, Other fatalities, Phase, Source, Narrative, Category, Accident report] |
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