DEN99LA108 · Beech B90
Beech B90 · Accident: hard landing
From Wiley Post Airport (PWA) to Q39
Event
- NTSB case
- DEN99LA108
- 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
- General aviation
- 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 B90
- Aircraft type
- Beechcraft 90
- 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
- N221NC
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Wiley Post Airport (PWA), Oklahoma City, OKTo Q39
- 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 91: General Aviation
- 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 · flare/touchdown
- 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
- Hard landing
- 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, main gear strut scissors › Failure, total
- Landing gear, main gear strut scissors › Fatigue
- Landing gear, main gear strut scissors › Overload
- Landing gear, main gear strut scissors › Previous damage
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The flight instructor said the airplane felt like it was being pushed down onto the runway. As power was added, the airplane touched down 'approximately 90 KIAS (a loss of 10 to 15 knots indicating a shear)' and there was a loud 'bang.' The airplane became airborne momentarily, then touched down again. The airplane departed the right side of the runway on its nose and left main landing gear. The owner-pilot receiving instruction said 'the bottom fell out and a moderately hard landing was made on the main gear. A pilot who witnessed the accident landed hard moments before. He said he had encountered a 'vertical wind shear.' He saw a large puff of blue gray smoke come out from beneath the right wing, followed by the tumbling right main gear. Metallurgical examination of the right scissors torque link disclosed multiple fractures and a crack in the upper link. The fractures were 'typical of fatigue cracking,' originating from 'multiple sites.' There was also corrosion pitting. Two other fracture sites were 'indicative of overstress.'
Probable cause
Overload failure of the right main landing gear scissors torque link precipitated by preexisting fatigue fractures. A factor was wind shear.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN99LA108
- Event ID
- 20001212X18985
- Case number
- DEN99LA108
- 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: 4ce10a7f5daa2a810e37307f30e77349a37b3bdb47b3faa7317482de3bcc9e30; retrieved 2026-09-22T14:45:13.732Z.