Portland Intnl Airport
Aircraft Accident/Incident Report

Portland, Oregon 97218
Wednesday, April 13, 1988 13:10 PDT

NTSB Narrative Summary Released at Completion of Accident

THE BOEING 727 WAS PUSHED BACK FM THE GATE COUNTERCLOCKWISE THROUGH AN ARC OF 90 DEGREES RESULTING IN MISPOSITIONING THE ACFT RELATIVE TO THE INTENDED TAXI DIRECTION. THE GROUND CREW (TUG AND SAFETY OPERATORS) ATTEMPTED TO RESOLVE THE OUT OF POSITION CONDITION BY CONTINUING THE PUSH BACK THROUGH A SECOND 90 DEGREE (COUNTERCLOCKWISE) ARC. THIS REQUIRED PUSHING THE AIRCRAFT UPSLOPE ACROSS THE RAMP. DURING THE SECOND 90 DEGREE ARC THE TUG BECAME POSITIONED APPROXIMATELY 90 DEGREES TO THE TOWBAR/AIRCRAFT LONGITUDINAL AXIS. THE DOWNSLOPE AND IDLE POWER CONDITIONS OVERPOWERED THE TUG'S BRAKING CAPACITY AND THE TOW BAR BROKE UNDER A BENDING LOAD ALLOWING THE AIRCRAFT TO ROLL FORWARD IMPACTING THE TUG. ALL THREE B-727 ENGINES WERE OPERATING AT IDLE THRUST.

NTSB Probable Cause Narrative

Not Yet Reported

Event Information

Type of Event Incident
Event Date 4/13/1988
Event Day of the Week Wednesday
Time of Event 1310
Event Time Zone Pacific Daylight Time
Event City PORTLAND
Event State OREGON
Event Country --
Zipcode of the event site 97218
Event Date Year 1988
Event Date Month 4
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport PORTLAND INTNL
Event Location Nearest Airport ID PDX
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 26
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1350 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID PDX
Elevation of weather observation facility 26
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 3300
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 20
Air Temperature at event time (in degrees celsius) 14
Dew Point at event time (in degress fahrenheit) 9
Wind Direction (degrees magnetic) 70
Variable Wind Indicator Unknown
Wind Speed (knots) 4
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 98
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 5000
NTSB Notification Source --
NTSB Notification Date Apr 13 1988 12:00AM
NTSB Notification Time 1400
Fiche Number and/or location -used to find docket information 35867
Date of most recent change to record Dec 13 2000 11:41AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N291AS
NTSB Number SEA88IA074
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage Minor
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BOEING
Aircraft Model 727-290
Aircraft Series Identifier 727-290
Aircraft Serial Number 21511
Certified Max Gross Weight 169000
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 145
Number of Engines 3
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Unknown
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed Unknown
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name GATX LEASING CORPORATION
Aircraft Owner Street Address 4 EMBARCADERO CENTER, STE.2200
Aircraft Owner City SAN FRANCISCO
Aircraft Owner State CA
Aircraft Owner Country
Aircraft Owner Zipcode 94111
Operator is an individual? --
Operator Name ALASKA AIRLINES, INC.
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address BOX 68900
Operator City SEATTLE
Operator State WA
Operator Country
Operator Zip code 98168
Operator Code ASAA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
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) Unknown
Second Pilot on Board Yes
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 1305
Departure Time Zone PDT
Destination Same as Local Flt --
Destination Airport Code PHX
Destination City PHOENIX
Destination State AZ
Destination Country
Specific Phase of Flight Taxi
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:30AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --