Seattle-Tacoma Int. Airport
Aircraft Accident/Incident Report

Seattle, Washington 98188
Sunday, December 28, 2008 7:00 PST

NTSB Narrative Summary Released at Completion of Accident

A Boeing 757-351 and a Boeing 737-832 were substantially damaged when the tails of both airplanes collided during the pushback process from two opposing terminal gates during night visual meteorological conditions. The flight crew and ground crew of the Boeing 737-832 reported that they had stopped, were in a static position, and in the final stages of disconnecting the tug when the collision occurred. The ground crew of the Boeing 757-351 reported that they never observed the Boeing 737-832 during their pushback process. Review of recorded communications tapes between the flight crews of both aircraft and the ramp controller revealed that the Boeing 757-351 was cleared to be pushed into the alleyway with its tail to the south. About 9 seconds later, the Boeing 737-832 was cleared for pushback into the alleyway with its tail to the north. The recorded communications tapes revealed that the ramp controller did not advise either aircraft of the opposing pushback operations. The controller stated that she thought that the Boeing 737-832 was requesting to push back from a different gate than they had requested; however, the recorded communications tapes clearly have flight crew of the Boeing 737 stating their correct gate in their initial call for a pushback clearance.

NTSB Probable Cause Narrative

The failure of the tug operator and wing walker of this airplane to maintain clearance with the other aircraft during the pushback process in dark night. Also causal was the ramp controller's misinterpretation of the other airplane's gate location and her improper clearance for both airplanes to simultaneously push back from nearly opposing gates.

Event Information

Type of Event Accident
Event Date 12/28/2008
Event Day of the Week Sunday
Time of Event 700
Event Time Zone Pacific Standard Time
Event City Seattle
Event State WASHINGTON
Event Country --
Zipcode of the event site 98188
Event Date Year 2008
Event Date Month 12
MidAir Collision Indicator --
On Ground Collision occurred ? Yes
Event Location Latitude 472659N
Event Location Longitude 1221842W
Event Location Airport Seattle-Tacoma Int. Airport
Event Location Nearest Airport ID SEA
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 433
Weather Briefing Completeness --
Investigator's weather source Weather Observation Facility
Time of the weather observation 653 Pacific Standard Time
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID SEA
Elevation of weather observation facility 433
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation PST
Lighting Conditions Night
Lowest Ceiling Height 1300
Lowest Non-Ceiling Height 800
Sky/Lowest/Cloud Conditions Scattered
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) 4
Dew Point at event time (in degress fahrenheit) 2
Wind Direction (degrees magnetic) 230
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 8
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 29.81
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 352
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 25549
NTSB Notification Source FAA Operations Center
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Jul 20 2009 11:55AM
User who most recently changed record johb
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft #2

Aircraft Registration Number N585NW N397DA
NTSB Number WPR09FA068A WPR09FA068B
Missing Aircraft Indicator -- --
Federal Aviation Reg. Part Part 121: Air Carrier Part 121: Air Carrier
Type of Flight Plan filed IFR IFR
Flight plan Was Activated? No No
Damage Substantial Substantial
Aircraft Fire None None
Aircraft Explosion None None
Aircraft Manufacturer's Full Name BOEING BOEING
Aircraft Model 757-351 737-832
Aircraft Series Identifier -- --
Aircraft Serial Number 32985 30537
Certified Max Gross Weight 271000 173000
Aircraft Category Airplane Airplane
Aircraft Registration Class -- --
Aircraft is a homebuilt? No No
Flight Crew Seats 3 3
Cabin Crew Seats 8 5
Passenger Seats 224 160
Total number of seats on the aircraft 235 168
Number of Engines 2 2
Fixed gear or retractable gear Retractable Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness Continuous Airworthiness
Date of Last Inspection Dec 27 2008 12:00AM Dec 27 2008 12:00AM
Airframe hours since last inspection -- --
Airframe Hours 23244 21347
ELT Installed Yes Yes
ELT Activated No Yes
ELT Aided Location of Event Site No No
ELT Type Unknown Unknown
Aircraft Owner Name NORTHWEST AIRLINES INC DELTA AIR LINES INC
Aircraft Owner Street Address 7500 AIRLINE DR DEPT C8960 HARTSFIELD INTL AIRPORT DEPT 595
Aircraft Owner City MINNEAPOLIS ATLANTA
Aircraft Owner State MN GA
Aircraft Owner Country USA USA
Aircraft Owner Zipcode 55450-1101 30320
Operator is an individual? No No
Operator Name NORTHWEST AIRLINES INC DELTA AIR LINES INC
Operator Same as Owner? Yes Yes
Operator Is Doing Business As -- --
Operator Address Same as Owner? Yes Yes
Operator Street Address 7500 AIRLINE DR DEPT C8960 HARTSFIELD INTL AIRPORT DEPT 595
Operator City MINNEAPOLIS ATLANTA
Operator State MN GA
Operator Country USA USA
Operator Zip code 55450-1101 30320
Operator Code NWAA DALA
Owner has at least one certificate Yes - certificate holder Yes - certificate holder
Other Operator of large aircraft? No No
Certified for Part 133 or 137 Operation -- --
Operator Certificate Number -- --
Indicates whether an air carrier operation was scheduled or not Scheduled Scheduled
Indicates Domestic or International Flight Domestic Domestic
Operator carrying Pax/Cargo/Mail Passenger Only Passenger Only
Type of Flying (Per_Bus / Primary) -- --
Second Pilot on Board Yes Yes
Departure Point Same as Event Yes Yes
Departure Airport Code SEA SEA
Departure City Seattle Seattle
Departure State WA WA
Departure Country USA USA
Departure Time -- --
Departure Time Zone PST PST
Destination Same as Local Flt -- --
Destination Airport Code MSP CVG
Destination City Minneapolis Covington
Destination State MN KY
Destination Country USA USA
Specific Phase of Flight -- --
Report sent to ICAO? -- --
Evacuation occurred -- --
Date of most recent change to record Jun 5 2009 8:41PM Jun 5 2009 8:45PM
User who most recently changed record stam stam
Since inspection or accident Time of Accident Time of Accident
Event Location Runway Number and Location N/A N/A
Runway Length -- --
Runway Width -- --
Sight Seeing flight No No
Air Medical Flight No No
Medical Flight -- --