Flight 990 · Boeing 767-232
Boeing 767-232 · Incident: airframe, component or system failure during initial climb
From Salt Lake City International Airport (SLC) to Dallas Fort Worth International Airport (DFW)
Event
- NTSB case
- DEN00IA023
- 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
- Airline
- 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
Boeing 767-232
- Aircraft type
- Boeing 767
- 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
- N111DN
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Salt Lake City International Airport (SLC)To Dallas Fort Worth International Airport (DFW), DALLAS-FT WORTH, TX
- 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 121: Air Carrier
- 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
- Initial climb
- 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
- Company maintenance personnel › Maintenance, overhaul, improper
- Landing gear, normal retraction/extension assembly › Failure, total
- Landing gear, normal retraction/extension assembly › Stress corrosion
Approximate · Estimated position: the centre of Salt Lake City, UT, the place the record names. Not the accident site.
NTSB narrative
The crew heard a loud noise and felt a vibration when the landing gear was retracted after takeoff. An emergency was declared, and the flight returned to Salt Lake City. When the landing gear was lowered, the nose and right main landing gear DOWN AND LOCKED lights illuminated, but a GEAR UNSAFE light illuminated for the left main landing gear. Following a low pass over the airport, maintenance personnel advised the landing gear appeared to be down and locked. An uneventful landing was made. Maintenance personnel informed the crew that the landing gear actuator had sheared and could not be pinned for towing. The part was later removed and examined. Stress corrosion cracking had occurred through 75% of the piston, followed by ductile separation. The corrosion had formed when a faulty fillet seal around the base of the rod end allowed moisture to enter the joint. The retract actuator was an original part, but it was determined that it had previously been reworked.
Probable cause
Total failure of the main landing gear retract actuator due to stress corrosion caused by the use of a faulty sealant by company maintenance personnel that allowed moisture to enter the joint. A factor was the use of an improper fillet seal.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN00IA023
- Event ID
- 20001212X20224
- Case number
- DEN00IA023
- 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: dc70717ab7f313a91dd8a849ea32e758a6c1f752c982dddf6084f74269101c5d; retrieved 2026-09-18T16:50:47.273Z.