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Alpha Aviation Flight 7980

17 Mar 1995 · Los Angeles, CA, United States

Beech 1900C · Incident: airframe, component or system failure on approach

From Mammoth Yosemite Airport (MMH) to Los Angeles International Airport (LAX)

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Event

NTSB case
LAX95IA142
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Incident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
0 · all aircraft and ground
Ground fatalities
0
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
Charter & commuter
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Beech 1900C

Aircraft type
Beechcraft 1900
Category
Airplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N1568W
Onboard fatalities
Unknown
Route
From Mammoth Yosemite Airport (MMH), Mammoth Lakes, CATo Los Angeles International Airport (LAX)
Aircraft age
Not recorded
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 135: Air Taxi & Commuter
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
Approach · VFR pattern final
First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Airframe, component or system failure
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Minor

Cause areas

  • Flight control, flap attachment › Disconnected
  • Flight control, flap attachment › Eroded
  • Flt control syst, wing flap control bearing › Shifted

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

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.

Probable cause

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.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record LAX95IA142
Event ID
20001207X03138
Case number
LAX95IA142
Dataset
historical-pre2008
Source SHA-256
89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: 214154c3d4dfe475d24dba7c5de0e5b126d853f08bd76a98b55ee40eeeeaca37; retrieved 2026-09-18T18:02:35.576Z.