Minneapolis-St Paul Intl/Wold- Airport
Aircraft Accident/Incident Report

Minneapolis, Minnesota 55111
Tuesady, May 1, 2001 14:37 CDT

NTSB Narrative Summary Released at Completion of Accident

The airplane was substantially damaged when it was struck by an aircraft tug during passenger boarding. The aircraft was parked and was being prepared for departure. The driver of the tug was moving the vehicle into position in order to connect the aircraft tow bar in preparation for pushback. He said that when he placed the tug into gear, it lurched forward into the parked aircraft. He said that pieces of the aircraft protruded through the windshield of the vehicle and pinned him into his seat. He said that he was unable to shift the vehicle into reverse and his leg was pinned on the accelerator pedal. Other ground workers in the area attempted to shut off the tug's engine. The driver said that the vehicle continued to drive forward until the engine was finally shut off. During the event, the pilot of the aircraft had applied the brakes when he noticed the unplanned movement of the airplane. The aircraft was pushed backward about 30 feet causing damage to the nose section of the fuselage. Subsequent to the accident, the tug was placed on jacks and a check performed. During the check it was found that the normal engine shutoff switch would not shut the engine off if the engine was operated at high throttle settings. It was further discovered that at high throttle settings, the brake system was not able to stop the rotation of the drive wheels. No anomalies were found during this test that would explain the lurching described by the tug driver. The tug had been involved in a previous incident where an aircraft was damaged. A report of the previous incident showed that the tug lurched when the driver was attempting to move the tug into position to connect to the aircraft. The tug manufacturer does not have records of operational problems associated with that model tug. The manufacturer also said that they were not aware of a history of lurching problems concerning the model tug in question. It was found that the distance from the cab of the tug to the nose of a DC-9 aircraft when the tow bar is attached is 4 feet 2 inches.

NTSB Probable Cause Narrative

The partial failure of the aircraft tug for undetermined reasons.

Event Information

Type of Event Accident
Event Date 5/1/2001
Event Day of the Week Tuesday
Time of Event 1437
Event Time Zone Central Daylight Time
Event City Minneapolis
Event State MINNESOTA
Event Country --
Zipcode of the event site 55111
Event Date Year 2001
Event Date Month 5
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
Event Location Airport MINNEAPOLIS-ST PAUL INTL/WOLD-
Event Location Nearest Airport ID MSP
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles 0
Degrees magnetic from airport 0
Airport Elevation 841
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1445 Central Daylight Time
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID MSP
Elevation of weather observation facility 841
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation CDT
Lighting Conditions Day
Lowest Ceiling Height 8000
Lowest Non-Ceiling Height 2500
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 25
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) 6
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.15
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries --
On Ground, Minor Injuries 2
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor 2
Injury Total None 42
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 11953
NTSB Notification Source FAA
NTSB Notification Date May 1 2001 12:00AM
NTSB Notification Time 1630
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Jul 2 2002 4:28PM
User who most recently changed record NTSB\MONR
Basic weather conditions Visual Meteorological Cond
FAA District Office Minneapolis, Minnesota

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9333
NTSB Number CHI01FA129
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? No
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Douglas
Aircraft Model DC-9-31
Aircraft Series Identifier --
Aircraft Serial Number 47246
Certified Max Gross Weight 108000
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 105
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection AAIP
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name NORTHWEST AIRLINES INC
Aircraft Owner Street Address 5101 Northwest Dr.
Aircraft Owner City Saint Paul
Aircraft Owner State MN
Aircraft Owner Country USA
Aircraft Owner Zipcode 55111
Operator is an individual? No
Operator Name --
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City --
Operator State --
Operator Country --
Operator Zip code --
Operator Code NWAA
Owner has at least one certificate --
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
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 No
Departure Airport Code MSP
Departure City MINNEAPOLIS
Departure State MN
Departure Country USA
Departure Time --
Departure Time Zone --
Destination Same as Local Flt --
Destination Airport Code PHL
Destination City PHILADELPHIA
Destination State PA
Destination Country USA
Specific Phase of Flight Standing
Report sent to ICAO? No
Evacuation occurred No
Date of most recent change to record Jun 17 2002 11:58AM
User who most recently changed record SULP
Since inspection or accident --
Event Location Runway Number and Location --
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --