Beechcraft 90B N37OU

Summary

On 11 April 2011 at about 15:15 local time, a Beechcraft 90B registered N37OU, operated by University of Oklahoma, Dept of Aviation, was involved in an incident near Chickasha, Oklahoma, United States. 4 people were on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

11 April 2011 at 15:15

Classification

Incident

Location

Chickasha, Oklahoma, United States

Nearest airport

Chickasha Municipal Airport (CHK)

Coordinates

35.0972, -97.9675

Aircraft

Beechcraft 90B

Registration

N37OU

Category

Airplane

Engines

2

Operator

University of Oklahoma, Dept of Aviation

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Norman → Norman

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

CEN11IA280

Nobody was injured.

The mechanic's improper installation of the aileron.

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

Read the full NTSB narrative

The certified flight instructor (CFI) reported that the airplane was on a downwind leg for landing when a pilot-rated passenger who was sitting in the cabin told him that the right aileron was partially separated from the airplane. The CFI took control of the airplane and landed it uneventfully. The post incident inspection of the airplane revealed that the two inboard aileron hinges were separated from the airframe. The screws (8 screws, 4 upper, 4 lower) which attached the aileron to the aileron hinge points were seated in the aileron skin, but did not screw into the corresponding nut plates on the aileron hinge points. The aileron was not damaged so a mechanic attached the aileron properly to the aileron hinge points and the airplane was returned to service. Maintenance records indicated that the airplane had undergone a phase inspection 10 days prior to the incident. During the phase inspection, the right aileron was removed to repair some light surface corrosion and was reinstalled on the airplane. The incident occurred 5.3 hours after the phase inspection was performed. Eight years prior to the accident, the aircraft manufacturer issued a communique which stated that their technical support department had received reports that during aileron installation, screws missed the nut plates on the aileron hinge points. It stated that this condition can go unnoticed.

Quoted verbatim from the NTSB record.