Status: | Definitief |
Datum: | maandag 9 mei 1988 |
Tijd: | 16:35 |
Type: |  Boeing 747-136 |
Luchtvaartmaatschappij: | British Airways |
Registratie: | G-AWND |
Constructienummer: | 19764/107 |
Bouwjaar: | 1971-01-20 (17 years 4 months) |
Aantal vlieguren: | 1868 |
Motoren: | 4 Pratt & Whitney JT9D-7A |
Bemanning: | slachtoffers: 0 / inzittenden: 18 |
Passagiers: | slachtoffers: 0 / inzittenden: 286 |
Totaal: | slachtoffers: 0 / inzittenden: 304 |
Schade: | Groot |
Gevolgen: | Repaired |
Plaats: | nabij Chicago-O'Hare International Airport, IL (ORD) ( Verenigde Staten)
|
Fase: | Nadering (APR) |
Soort vlucht: | Internationale lijnvlucht |
Vliegveld van vertrek: | London-Heathrow Airport (LHR/EGLL), Verenigd Koninkrijk |
Vliegveld van aankomst: | Chicago-O'Hare International Airport, IL (ORD/KORD), Verenigde Staten |
Beschrijving:The aircraft was on final approach to Chicago O'Hare Airport when a structural failure of the number three flap track occurred. The aircraft 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 aircraft 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.
Probable Cause:
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."
Bronnen:
» NTSB
Veiligheidsmaatregelen
NTSB issued 3 Safety Recommendations
Issued: 30-SEP-1988 | To: FAA | A-88-131 |
FOR BOEING 747 AIRPLANES WITH THE EARLY PRODUCTION FLAP TRACKS, REQUIRE A MAGNIFIED VISUAL OR OTHER NONDESTRUCTIVE INSPECTION, WITHIN 20 FLIGHT CYCLES OF ANY PREVIOUS INSPECTION, OF THE FORWARD BOLT HOLE BORES OF THE INBOARD FLAP TRACKS FOR CORROSION PITTING AND CRACKS USING DAMAGE TOLERANCE CRITERIA DEVISED BY BOEING, AND ESTABLISH PERIODIC INSPECTION INTERVALS FOR THE BOLT HOLE BORES CONSISTENT WITH EARLY DETECTION OF CORROSION PITTING IN THE BORES. (Closed - Acceptable Action) |
Issued: 30-SEP-1988 | To: FAA | A-88-132 |
ISSUE AN AIR CARRIER OPERATIONS BULLETIN TO ADVISE ALL OPERATORS OF BOEING 747 AIRPLANES CONFIGURED WITH THE EARLY PRODUCTION FLAP TRACKS OF THE ADVANTAGES OF OPERATING THESE AIRPLANES WITH A MAXIMUM OF 25 DEGREES-FLAP EXTENSION. (Closed - Acceptable Alternate Action) |
Issued: 30-SEP-1988 | To: FAA | A-88-133 |
REQUIRE PROMPT REPLACEMENT OF ALL EARLY PRODUCTION FLAP TRACKS ON INBOARD AND OUTBOARD FLAPS ON BOEING 747 AIRPLANES WITH NEW PRODUCTION TRACKS, AND INCLUDE THESE NEW TRACKS IN THE BOEING 747 SUPPLEMENTAL STRUCTURAL INSPECTION PROGRAM. (Closed - Acceptable Action) |
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Foto's
Kaart
Deze kaart geeft het vliegveld van vetrek weer en de geplande bestemming van de vlucht. De lijn tussen de vliegvelden geeft
niet de exacte vliegroute weer.
De afstand tussen London-Heathrow Airport en Chicago-O'Hare International Airport, IL bedraagt 6297 km (3936 miles).
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.