|Title:||Engine damage in climb, Boeing 747-236B, G-BDXH, 21 May 1996|
|Micro summary:||A Boeing 747 was hit by lightning on the #4 engine, resulting in a Cowl Overheat light and a return to the origin.|
|Event Time:||1996-05-21 at 1118 UTC|
|Publishing Agency:||Aircraft Accident Investigation Board (AAIB)|
|Publishing Country:||United Kingdom|
|Site of event:||20 nm southwest of London Gatwick Airport|
|Departure:||Gatwick Airport, London, England|
|Airplane Type(s):||Boeing 747-236B|
|Type of flight:||Revenue|
|Executive Summary:||The aircraft took off at 1113 hrs from Runway 26L at Gatwick, bound for Lagos (Nigeria). The aircraft was cleared on a Bogna1M Standard Instrument Departure, which involved climbing straight ahead initially for 4 nm before turning left onto a southerly track, climbing to 5,000 feet altitude. At the start of the left turn, ATC requested the aircraft to take up a heading of 230° for traffic separation. The flight crew requested a turn onto 240° to avoid weather. The Flight Data Recorder (see below) indicated that engine anti-ice on was selected for all four engines at around this time. The aircraft was then cleared to climb to 6,000 feet altitude. |
As the aircraft reached 6,000 feet there was a loud bang as the aircraft was struck by lightning in the region of the No 4 powerplant, after which the 'COWL OV HT' (Cowl Overheat) amber caption illuminated on the centre panel. A similar caption also appeared for the No 4 engine on the pilot's overhead panel. The aircraft continued a normal climb and proceeded on the planned route. Company maintenance control was contacted by radio. Some diagnostic checks were carried out on the system and it was confirmed that the No 4 engine Cowl Anti-Ice system was inoperative. As thunderstorms and icing conditions were forecast further down the route, the commander decided to return to London Gatwick Airport. In consultation with French ATC, a right turn was commenced at FL330, just south of Limoges, at 1219 hrs.
Some 2,000 kg of fuel was dumped during the return in order to be comfortably below maximum permitted landing weight. While approaching Mayfield VOR during the Gatwick Standard Arrival, the crew became aware that both the No 1 and 2 VHF Navigation receivers were inoperative, and they were thus unable to receive the ILS Localiser signal. Glidepath indications were normal. A radar monitored visual approach was carried out to Runway 26L, where the aircraft landed uneventfully at 1338 hrs. After landing it was observed that most of the fin tip cap was missing. The crew filed a company Air Safety Report and transferred across to another aircraft to operate the flight, which finally departed for Lagos at 1651 hrs.
An aftercast from the Meteorological Office indicated that, at the time of the lightning strike, a cold front was just clearing Kent with an unstable westerly airstream being established over Sussex and Kent. The Meteorological Office radar showed one storm cell 10 nm south of Gatwick at 11:20:23 hrs. A thunderstorm was also reported at Manston, Kent at 1100 hrs.
|Learning Keywords:||Operations - Bang, pop, crack, sizzle!|
|Operations - Lightning|
|Systems - Engine - Contained Engine Failure|
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