FLIGHT FINDINGSAVIATION OCCURRENCE MAP
Back to map

Southwest Airlines Boeing 737-7H4 incident

22 Dec 2011 · Denver, CO, United States Possible conflict

Boeing 737-7H4 · Incident during pushback

From Denver International Airport (DEN) to Los Angeles International Airport (LAX)

Report a problem

Narrative check · The NTSB narrative appears to contradict this record's location. Values are shown as recorded, not corrected; compare with the narrative.

Event

NTSB case
CEN12IA123
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
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
Airline
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

Boeing 737-7H4

Aircraft type
Boeing 737
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
N469WN
Onboard fatalities
Unknown
Route
From Denver International Airport (DEN), Denver, COTo Los Angeles International Airport (LAX), Los Angeles, CA
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
Pushback/towing
Defining eventThe 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
Miscellaneous/other
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

  • Personnel issues › Physical

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

The passengers and the flight crew were seated, and the ground crew was preparing to push the airplane away from the gate. The snowplow was conducting snow removal operations in clean-up mode. According to a witness, the snowplow was traveling eastbound behind the airplane and just north of the vehicle service road. The snowplow passed the airplane and then initiated a gradual turn to the right. The snowplow continued around 180 degrees and hit the airplane on the left side near the empennage.

The snowplow operator reported that he fell asleep while driving. The investigation revealed that the snowplow operator reported for his shift at 1730 the day before the incident and worked until 0200 the next morning. The snowplow operator slept in his supervisor’s vehicle, which was actively involved in the snow removal operations. At 0800, the snowplow operator resumed snow removal operations, and he had been working for about 6.5 hours when the incident occurred. The snowplow operator had an opportunity to sleep for 6 hours in his supervisor’s vehicle; however, since the vehicle was being operated, he probably did not get uninterrupted sleep and most likely got less than 6 hours of sleep. Although the investigation was unable to determine how long the snowplow operator had been awake on the day before the accident or how long he had slept in his supervisor’s vehicle, he was most likely fatigued. The company did not have, and was not required to have, guidance or a policy addressing fatigue management.

Probable cause

The snowplow operator’s incapacitation due to fatigue, which resulted in the snowplow contacting a parked airplane. Contributing to the incident was the company’s lack of a policy regarding employee fatigue.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record CEN12IA123
Event ID
20120105X34138
Case number
CEN12IA123
Dataset
full-current
Source SHA-256
5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: 86cd5a629d7d515b9a9d344b3e14a9830f2022926fbc24a0477710caea1d7bdc; retrieved 2026-09-15T17:02:39.695Z.