Probable cause
The first officer's unannounced advancement of the left engine throttle, which led to a sustained application of high thrust that caused the airplane to impact the tug.
NTSB analysis
The first officer indicated that he advanced the left engine throttle during the airplane's taxi in order to clear what he suspected was a stuck bleed air valve. Although he suspected that he had only moved the throttle "about an inch", FDR data revealed it had been advanced to and remained at an extremely high power setting for approximately 28 seconds. This action, which occurred without the knowledge of the captain or the tug operator and without application of the parking brakes, resulted in a substantial increase in thrust that overwhelmed the tug's resistance until the airplane impacted the tug.
Text from the NTSB. Open the NTSB docket for DCA09FA022 for the full record.
Event
- Date
- Dec 26, 2008
- Type
- Accident
- Place
- Los Angeles Intl Airport, California
- Nearest airport
- Los Angeles Intl Airport (LAX)
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Mcdonnell Douglas DC-9-83
- N-number
- N9617R
- Category
- Airplane
- Damage
- Substantial
- Operating rule
- Part 121 (airline)
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.