Alpine Air Beech B99 accident
Beech B99 · Accident: loss of control on ground/water during landing
From Billings Logan International Airport (BIL) to Missoula Montana Airport (MSO)
Event
- NTSB case
- SEA00LA183
- 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
- Accident
- 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 B99
- Aircraft type
- Beechcraft 99
- 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
- N99TH
- Operator
- Alpine Air
- Onboard fatalities
- Unknown
- Route
- From Billings Logan International Airport (BIL), Billings, MTTo Missoula Montana Airport (MSO)
- 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
- Landing
- 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
- Loss of control on ground/water
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Landing gear, normal brake system › Contamination
- Landing gear, normal brake system › Locked
- Pilot in command › Directional control, not possible
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airplane touched down on the centerline of runway 29. When the pilot applied brakes 'the right brake locked up' and the airplane immediately veered to the right. The pilot applied left brake, left rudder and reversed the left propeller, however, the airplane continued to the right. The airplane collided with a taxiway light and runway marker before departing the right side of the runway. The airplane sustained substantial damage to the fuselage. Post-accident photographs of the airplane revealed ice and snow deposits on the cargo pod, right lower engine nacelle, main landing gear strut and right dual brake assembly. The landing runway in Missoula was dry, however, the departure runway at Billings was contaminated with snow and slush. Post-accident inspection of the airplane, by inspectors from the FAA Helena, Montana, Flight Standards District Office, revealed no evidence of system mechanical malfunction that would result in a brake failure.
Probable cause
A loss of directional control due to a brake locked as a result of snow and ice contamination.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA00LA183
- Event ID
- 20001212X22076
- Case number
- SEA00LA183
- 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: ce7b635b6f6bb9971e1a35c5483ce0a85785c5180c3e3fa1ec2c7673a92a20d8; retrieved 2026-09-18T16:24:24.473Z.