Cessna T207 N91081

Summary

On 13 April 1990 at about 21:58 local time, a Cessna T207 registered N91081, operated by Windrock Aviation, was involved in an accident near Grand Canyon, Arizona, United States. 7 people were on board and 7 were seriously injured. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

13 April 1990 at 21:58

Classification

Accident

Location

Grand Canyon, Arizona, United States

Nearest airport

Grand Canyon (GCN)

Coordinates

36.0296, -112.0205

Aircraft

Cessna T207

Registration

N91081

Category

Airplane

Engines

1

Operator

Windrock Aviation

Operating rule

Part 135: Air Taxi & Commuter

Purpose of flight

Unknown

Phase of flight

Not recorded

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

LAX90FA145

7 people were seriously injured.

IMPROPER ADJUSTMENT OF THE TURBO-CHARGER ABSOLUTE PRESSURE CONTROLLER, AND IMPROPER MANIPULATION OF THE POWER PLANT CONTROLS BY THE PILOT DURING THE GO-AROUND. FACTORS RELATED TO THE ACCIDENT WERE: FAILURE OF COMPANY MANAGEMENT TO PROPERLY TRAIN THE PILOT IN ACCORDANCE WITH THE APPROVED COMPANY TRAINING PROGRAM, AND THE PILOT'S LACK OF EXPERIENCE IN TURBO-CHARGED ENGINE OPERATIONS.

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

Read the full NTSB narrative

ACCORDING TO WITNESSES, THE ACFT WAS ABOUT TO TOUCHDOWN FROM A NORMAL APCH TO RWY 21, WHEN IT ENCOUNTERED VARIALBLE WIND CONDS & BALLOONED TO ABOUT 70' AGL. THE PLT INITIATED A GO-AROUND. SHORTLY THEREAFTER, WITNESSES OBSERVED A PUFF OF SMOKE EMANATE FROM THE ACFT, THEN THE PLT TRANSMITTED THAT THE FLT WAS 'GOING DOWN.' SUBSEQUENTLY, THE ACFT COLLIDED WITH TREES ON WOODED TERRAIN ABOUT 1/2 MI FROM THE DEP END OF THE RWY. AN EXAM REVEALED A LACK OF POWER SIGNATURES ON THE PROP; EVIDENCE OF SOOTING WAS FOUND ON THE SPARK PLUGS (INDICATING A RICH MIXTURE). TESTING OF THE TURBO-CONTROLLER REVEALED EVIDENCE THAT IT HAD BEEN ADJUSTED TO A LOW SETTING; THE TURBO WOULD ONLY PRODUCE A MAXIMUM AIR FLOW EQUAL TO HIGH CRUISE POWER. THE ENG MANUFACTURER RPRTD THAT THIS SITUATION COULD PRODUCE AN OVER-RICH MIXTURE, PARTICULARILY IF THE THROTTLE AND/OR MIXTURE CONTROLS WERE IMPROPPERLY MANIPULATED. THE PILOT LACKED EXPERIENCE IN ACFT WITH TURBO-CHARGED ENGS & HE WAS NOT TRAINED IAW THE COMPANY TRAINING PROGRAM.

Quoted verbatim from the NTSB record.