Praker Thorp T18C N86BP

Summary

On 24 May 1994 at about 20:29 local time, a Praker Thorp T18C registered N86BP was involved in an accident near Phoenix, Arizona, United States. One person was on board and one died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

24 May 1994 at 20:29

Classification

Accident

Location

Phoenix, Arizona, United States

Coordinates

33.6810, -112.0898

Aircraft

Praker Thorp T18C

Registration

N86BP

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Unknown

Phase of flight

Not recorded

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

FTW94FA176

1 person died.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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.

Quoted verbatim from the NTSB record.