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ASN Wikibase Occurrence # 39501
Last updated: 1 April 2019
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Date:24-MAY-1994
Time:13:29
Type:Silhouette image of generic T18 model; specific model in this crash may look slightly different
Thorp T-18C
Owner/operator:private
Registration: N86BP
C/n / msn: 1386
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Phoenix, AZ -   United States of America
Phase: Take off
Nature:Unknown
Departure airport:
Destination airport:
Investigating agency: NTSB
Narrative:
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. 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.

Sources:

NTSB: https://www.ntsb.gov/ntsb/brief.asp?ev_id=20001206X01274


Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
21-Dec-2016 19:23 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]

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