Delta Air Lines Flight 229
Boeing 767-332 · Incident: airframe, component or system failure while taxiing
From Salt Lake City International Airport (SLC) to Portland International Airport (PDX)
Event
- NTSB case
- SEA96IA131
- 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 767-332
- 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
- N136DL
- Operator
- Delta Air Lines
- Onboard fatalities
- Unknown
- Route
- From Salt Lake City International Airport (SLC), UTTo Portland International Airport (PDX), Portland, OR
- 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
- Taxi · to runway
- 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 › Generator, not removed
- Company maintenance personnel › Procedures/directives, not complied with
- Electrical system, generator › Overtemperature
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During taxi for departure a 'R GEN OFF' and 'R GEN DRIVE' EICAS message illuminated indicating a malfunction of the right integrated drive generator (IDG), and the crew returned the Boeing 767 to the gate. Maintenance was notified, and a mechanic was dispatched to the aircraft. The mechanic reported that he 'assumed (the) crew had disconnected (the) IDG.' The captain reported that he was advised by the mechanic that 'the IDG is disconnected.' The aircraft was prepared and released according to its MEL for the flight using the left IDG and APU generator. During climbout a 'R STARTER CUTOUT' EICAS message illuminated followed by a fire warning on the right engine. Both fire bottles were exhausted, the fire warning extinguished, and the aircraft was returned to Salt Lake City, for emergency landing on runway 16L. Postincident examination of the engine revealed the fire-damaged remains of the right IDG and its magnesium housing. A download of digital data from the aircraft revealed that the original EICAS and IDG annunciations were related to low oil pressure within the IDG. An FAA inspector, who examined the aircraft immediately following the event, found the right IDG disconnect switch still safety wired (the IDG cannot be disconnected without breaking the wire and depressing the switch). The MEL dispatch procedure developed by the carrier did not address the need to run the associated engine at or above idle in order to successfully disconnect the IDG.
Probable cause
failure of maintenance personnel to properly disconnect (disengage) the right integrated drive generator (IDG) in compliance with the MEL dispatch procedure, which allowed the right IDG to overheat. Factors relating to the incident were: low oil pressure in the right IDG, and insufficiently defined company developed dispatch procedure.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA96IA131
- Event ID
- 20001208X06102
- Case number
- SEA96IA131
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1996-06-20.
- API snapshot SHA-256: 10df1cab2d1ac0740557fcadf64be5781e7256df5dbb6e3b0ca3bc36945a6016; retrieved 2026-09-18T17:49:35.213Z.