Mesa Airlines Beech 1900D incident
Beech 1900D · Incident: airframe, component or system failure on approach
From Walla Walla Regional Airport (ALW) to Seattle–Tacoma International Airport (SEA)
Event
- NTSB case
- SEA97IA051
- 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 1900D
- 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
- N75ZV
- Operator
- Mesa Airlines
- Onboard fatalities
- Unknown
- Route
- From Walla Walla Regional Airport (ALW), Walla Walla, WATo Seattle–Tacoma International Airport (SEA)
- 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 commenced a rapid, uncommanded roll to the right when the 35-degree flap setting was selected. The flying pilot (1st officer) was able to counter the roll by applying almost full opposite aileron, during which time, he felt the aileron jam momentarily and then break free. The airplane landed without further incident. An examination revealed that the inboard, aft end of the right wing outboard flap was detached from the wing flap track. This resulted in flap asymmetry and mechanical interference with the aileron. The flap track roller bearing was seized and the flap mounting bracket was torn and separated from the bearing. The bearing outer roller was loose and could be shifted axially on the bearing outer ring. This allowed the outer roller flange to wear against and eventually tear through the flap mounting bracket. The operator was not using the most recent (revised) Beech 1900D maintenance manuals at the time of the incident and the airplane had not been subjected to a detailed inspection of the flap roller brackets, roller bearings, and attachment hardware as outlined in revised sections of the manual.
Probable cause
an axial shift of the aft flap track bearing's outer roller, resulting in erosion and failure of the flap track bracket/bearing assembly. A factor relating to the incident was: inadequate inspection of the flap roller bearing/bracket assemblies.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA97IA051
- Event ID
- 20001208X07358
- Case number
- SEA97IA051
- 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: 02d35c92bcff0da8aa597994eae178a524f09a990ecdf359f44a709e56519a8a; retrieved 2026-09-18T17:43:07.489Z.