Alpine Aviation Beech 99A accident
Beech 99A · Accident: in flight collision with object on approach
From Great Falls International Airport (GTF) to Billings Logan International Airport (BIL)
Event
- NTSB case
- SEA05LA010
- 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
- Unknown
- 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
- Instrument Meteorological Cond
Beech 99A
- 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
- N955AA
- Operator
- Alpine Aviation
- Onboard fatalities
- Unknown
- Route
- From Great Falls International Airport (GTF), Great Falls, MTTo Billings Logan International Airport (BIL), Billings, MT
- 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 · IFR initial approach
- 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
- In flight collision with object
- 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
- Pilot in command › Decision height, not maintained
- Pilot in command › IFR procedure, not followed
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
During a night instrument landing system (ILS) approach to minimums, two low altitude alerts were issued by the air traffic controller to the pilot of the airplane. Following the second alert, the pilot executed a missed approach and reported instrument flags. During the climb, the pilot found that the landing gear would not retract. He recycled the gear and attempted to lower it manually; however, he was unable to get a green light for the right main landing gear. He requested to proceed to another airport and upon arriving there executed an ILS approach without any problems. During the landing roll, the right main landing gear collapsed. Examination of the airplane revealed that the upper drag brace for the right main landing gear was torn away from the spar. Examination of the roof of a gun club building, located about 1.65 miles from the runway threshold (at the airport where the pilot executed a missed approach) and 607 feet left of centerline, revealed two impact marks spaced about 14 feet apart, a distance corresponding to the main gear width of the airplane. Additionally, landing gear drag brace pieces identified as coming from the airplane were found about 80 yards from the building. The elevation of the building roof was about 35 feet below the decision height for the approach, indicating the airplane had descended below decision height prior to reaching the middle marker. The FAA conducted a flight inspection of the ILS and found the facility operation to be satisfactory. The navigational equipment in the accident airplane was tested, and no anomalies were found that would have affected an ILS approach.
Probable cause
the pilot's failure to follow the instrument approach procedure, which resulted in a premature descent below the decision height and subsequent collision with a building.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA05LA010
- Event ID
- 20041109X01795
- Case number
- SEA05LA010
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (5)
- 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: local date, investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2004-10-18.
- API snapshot SHA-256: 6a45fa9dc234a97570de7b6e3ca79de6111d2431f9c7c15ddfcb8d4382fa7127; retrieved 2026-09-18T15:15:04.431Z.
- The NTSB's operator name is blank for N955AA; the operator shown is the name the NTSB's other records give its FAA operator code, TIMA.