Individually Owned: 150,657
Corporate Owned: 137,281
Denver International Airport
Aircraft Accident/Incident Report
Denver, Colorado
Thursday, December 22, 2011 14:37 MST
NTSB Narrative Summary Released at Completion of Accident
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.
NTSB Probable Cause Narrative
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.
Event Information
| Type of Event | Incident |
| Event Date | 12/22/2011 |
| Event Day of the Week | Thursday |
| Time of Event | 1437 |
| Event Time Zone | Mountain Standard Time |
| Event City | Denver |
| Event State | COLORADO |
| Event Country | -- |
| Zipcode of the event site | -- |
| Event Date Year | 2011 |
| Event Date Month | 12 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | -- |
| Event Location Longitude | -- |
| Event Location Airport | Denver International Airport |
| Event Location Nearest Airport ID | DEN |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | 5434 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1453 Mountain Standard Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | KDEN |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | MST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 1100 |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | -- |
| Sky Condition for Lowest Ceiling | Overcast |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | -7 |
| Dew Point at event time (in degress fahrenheit) | -10 |
| Wind Direction (degrees magnetic) | 80 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 4 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.28 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 133 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 29919 |
| NTSB Notification Source | FAA ANM ROC |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Jun 20 2012 7:41PM |
| User who most recently changed record | snyg |
| Basic weather conditions | Instrument Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N469WN |
| NTSB Number | CEN12IA123 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | No |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOEING |
| Aircraft Model | 737-7H4 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 33859 |
| Certified Max Gross Weight | -- |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 140 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Dec 17 2011 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 27563 |
| ELT Installed | Unknown |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | SOUTHWEST AIRLINES CO |
| Aircraft Owner Street Address | PO BOX 36611 |
| Aircraft Owner City | DALLAS |
| Aircraft Owner State | TX |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 75235-1611 |
| Operator is an individual? | No |
| Operator Name | SOUTHWEST AIRLINES CO |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | PO BOX 36611 |
| Operator City | DALLAS |
| Operator State | TX |
| Operator Country | USA |
| Operator Zip code | 75235-1611 |
| Operator Code | SWAA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | SWAA304A |
| Indicates whether an air carrier operation was scheduled or not | Scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | Yes |
| Departure Airport Code | DEN |
| Departure City | Denver |
| Departure State | CO |
| Departure Country | USA |
| Departure Time | -- |
| Departure Time Zone | MST |
| Destination Same as Local Flt | -- |
| Destination Airport Code | LAX |
| Destination City | Los Angeles |
| Destination State | CA |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | May 9 2012 5:40PM |
| User who most recently changed record | kaij |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |