- Date
- May 9, 1988, 16:35 local (21:35 UTC)
- Place
- Chicago, IL
- Injuries
- 304 uninjured
- Damage
- Substantial damage
- Phase of flight
- Approach
- Aircraft
- GAWNDBoeing 747-136
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 25, 1990
- Report
- Approved by Office Director
- Safety recommendations
- Yes
- Case key
- 13943
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
Failure of the number three flap track due to stress corrosion cracking. Factors contributing to this failure are insufficient design of the member and inadequate inspection and maintenance procedures to detect cracks before they propagate to a critical length.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
The acft was on final approach to Chicago o'hare inter'l airport when a structural failure of the number three flap track occurred. The acft sustained substantial damage to the left wing, left inboard flap assembly, left inboard spoilers and spoiler support beam. The pilot experienced significant uncommanded roll and yaw, but regained control of the acft and executed an uneventful landing. The investigation has revealed a history of flap track cracking problems associated with stress corrosion and design inadequacy. A design change of the member was accomplished in 1971 by the manufacturer, but flap tracks of the earlier design were allowed to remain in service on 239 aircraft. The airworthiness directives and service bulletins applicable to this particular structural member are not adequate in methodology and periodicity to ensure crack detection, and do not require inspection for the cause of the crack-corrosion pits.
Aircraft
- Registration
- GAWND
- Reported as
- Boeing 747-136
- Category
- Airplane
- Serial number
- 19764
- Airframe hours
- 1,868
- Engine
- P&W JT9D-7, 40,000 lbs thrust, turbo fan
- Damage
- Substantial damage
- Flight
- Part 129
- Operator
- British Airways, doing business as British Airways
- Registered owner
- British Airways
- Airworthiness certificate
- Standard, Transport
- Last inspection
- Continuous airworthiness · March 9, 1988
- Departed
- EGLL · London, OF
- Destination
- ORD
- Flight plan
- IFR
- Airport
- ORD · Chicago O'Hare, runway 27L, 10,140 × 150 ft, concrete
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 41
- Certificate
- Airline transport
- Airplane ratings
- Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, Valid Medical--no waivers/lim.
- Seat
- Left
- Flight hours
- 6,978 total · 1,815 in this make and model · 2,584 as pilot in command · 196 in the last 90 days · 70 in the last 30 days · 8 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 220° at 16 knots, gusting 26
- Visibility
- 3 statute miles
- Lowest ceiling
- 1,000 ft broken
- Temperature
- 55 °F, dew point 55 °F
- Altimeter
- 29.00 inHg
- Observed at
- ORD, 5 nm away