Beechcraft 1900C N1568W

Summary

On 17 March 1995 at about 18:50 local time, a Beechcraft 1900C registered N1568W, operated by Alpha Aviation, was involved in an incident near Los Angeles, California, United States. 19 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

17 March 1995 at 18:50

Classification

Incident

Location

Los Angeles, California, United States

Nearest airport

Los Angeles International (LAX)

Coordinates

33.9497, -118.4006

Aircraft

Beechcraft 1900C

Registration

N1568W

Category

Airplane

Engines

2

Operator

Alpha Aviation

Operating rule

Part 135: Air Taxi & Commuter

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Mammoth Lakes → Unknown

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

LAX95IA142

Nobody was injured.

AN AXIAL SHIFT OF THE OUTER BEARING ROLLER FOR AN UNDETERMINED REASON, RESULTING IN EROSION AND FAILURE OF THE FLAP TRACK HINGE BRACKET/BEARING ASSEMBLY. FACTORS RELATING TO THE INCIDENT WERE: THE ROLLER BEARING AND ASSOCIATED BRACKET ASSEMBLY WITHIN THE INTERIOR OF THE FLAP STRUCTURE COULD NOT BE ADEQUATELY INSPECTED WITHOUT DISASSEMBLY; AND LACK OF INSPECTION CRITERIA IN THE MANUFACTURER'S MAINTENANCE MANUAL CONCERNING FLAP ROLLER/HINGE BRACKET ASSEMBLIES.

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

Read the full NTSB narrative

WHILE ON FINAL APPROACH, THE AIRPLANE EXPERIENCED A RAPID, UNCOMMANDED ROLL TO THE LEFT WHEN THE 35-DEGREE FLAP SETTING WAS SELECTED. THE PILOT WAS ABLE TO COUNTER THE ROLL BY APPLYING FULL OPPOSITE AILERON AND LANDED WITHOUT FURTHER INCIDENT. AN EXAMINATION REVEALED THAT THE WING FLAPS HAD BEEN FULLY EXTENDED IN THE AFT DIRECTION, BUT THAT THE INBOARD TRAILING EDGE OF THE LEFT OUTBOARD FLAP HAD BEEN FORCED UPWARD ABOUT 3 INCHES. THE INBOARD AFT FLAP TRACK ROLLER BEARING ASSEMBLY, INCLUDING THE ATTACHING BOLT AND WASHER, HAD PULLED THROUGH THE SKIN OF THE FLAP TRACK HINGE BRACKET. AN ANALYSIS OF THE FAILED PARTS BY BEECH REVEALED THAT THE OUTER ROLLER WAS LOOSE ON THE BEARING AND COULD BE SHIFTED AXIALLY. A CIRCULAR WEAR PATTERN MATCHING THE DIAMETER OF THE OUTER ROLLER FLANGE WAS FOUND ON THE PORTION OF FLAP TRACK HINGE BRACKET WHICH HAD PULLED OUT. BEECH CONCLUDED THAT THE BEARING OUTER ROLLER HAD SHIFTED ON THE ROLLER ELEMENT BEARING AND ALLOWED THE OUTER ROLLER FLANGE TO WEAR AGAINST THE SIDE OF THE FLAP HINGE BRACKET UNTIL THE BEARING ASSEMBLY WAS PULLED OUT. THE FAILED FLAP TRACK HINGE BRACKET AND BEARING ASSEMBLY IS CONTAINED WITHIN THE INTERIOR OF THE FLAP STRUCTURE.

Quoted verbatim from the NTSB record.