# NTSB SEA88IA074: Boeing 727-290, N291AS, Portland, OR, April 13, 1988

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: April 13, 1988, 13:10 local (20:10 UTC)
- Place: Portland, OR
- Coordinates: 45.569534, -122.589134 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.5695&lon=-122.5891&mi=10
- Phase of flight: [Pushback/towing](https://openairdocs.org/ntsb-phases/200) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 98 uninjured
- Status: Completed, report January 25, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 40742
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA88IA074
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40742/pdf
- Page: https://openairdocs.org/ntsb/SEA88IA074

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- On ground/water collision with object, taxi - pushback/tow
  - terrain condition - uphill (contributing factor)
  - aircraft handling - improper, ground personnel (cause)
  - communications - not understood, ground personnel (contributing factor)

## Analysis

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.

## Aircraft

- Registration: N291AS (not matched to a registry record)
- Reported make and model: BOEING 727-290
- Category: Airplane
- Serial number: 21511
- Engines: P&W JT8D-217 14500 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 121
- Operator: Alaska Airlines, Inc.
- Registered owner: Gatx Leasing Corporation
- Airworthiness certificate: Standard, Transport
- Destination: PHX, PHOENIX, AZ
- Flight plan: IFR
- Airport: PDX, Portland Intnl

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 52; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 17,000 total, 15,000 in this make and model, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 70° at 4 knots
- Visibility: 20 statute miles
- Lowest ceiling: 3,300 ft overcast
- Temperature: 57 °F, dew point 48 °F
- Altimeter: 29.00 inHg
- Observed at: PDX

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19880413026329I](https://openairdocs.org/incident/19880413026329I), Apr 13, 1988: Boeing 727290, Portland, OR, Minor damage. Aircraft being repositioned to correct heading after tug driver error. Tow bar broke, allowing aircraft to hit tug.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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