|Title:||Main gear collapse on landing, McDonnell Douglas MD-83, EC-FXI, Liverpool, 2001-05-10|
|Micro summary:||The main landing gear of this MD-82 collapsed on landing.|
|Event Time:||2001-05-10 at 1232 UTC|
|Publishing Agency:||Aircraft Accident Investigation Board (AAIB)|
|Publishing Country:||United Kingdom|
|Site of event:||Liverpool airport|
|Departure:||Son Sant Joan Airport, Palma de Mallorca, Balearic Islands, Spain|
|Destination:||Liverpool John Lennon Airport, Liverpool, England|
|Airplane Type(s):||McDonnell Douglas MD-83|
|Type of flight:||Revenue|
|Executive Summary:||The aircraft carried out an automatic landing at Liverpool at 1232 hrs with the first officer (FO) being the pilot flying. The right main landing gear collapsed on touchdown and the commander took over control shortly afterwards. The aircraft continued travelling along the runway, maintaining approximately the centreline, and came to rest with the right wing in contact with the ground. A successful passenger evacuation was carried out using the forward escape slides and the left overwing emergency exit. |
The following causal factors were identified:
1 The right Main Landing Gear (MLG) cylinder failed immediately upon touchdown due to the application of spin-up drag loads on a section of the cylinder containing a major fatigue crack 3.2 mm long and 1.0 mm deep and several other associated smaller cracks.
2 The origins of these fatigue cracks could not be identified but other embryonic cracks were found which were associated with surface irregularities arising from a grit-blasting process during manufacture. Abnormal loading, possibly due to an occurrence of a mode of fore-and-aft vibration known as 'gear walking' is thought to have been responsible, at some time in the aircraft's history, for propagating the cracks to a depth at which continued growth was possible under normal loading. Alternatively, some abnormal loading may have relaxed the beneficial compressive surface stresses induced by shot-peening at the critical section and allowed propagation from the same surface defects.
3 Inspection and other mandatory preventive measures taken following two similar accidents did not prevent the occurrence of this third accident. This was probably due to the small size of cracks which are required to be detected before reaching a critical dimension.
|Learning Keywords:||Operations - Evacuation|
|Operations - Runway Excursion|
|Systems - Landing Gear|
|Systems - Landing Gear - MLG Collapse|
|Close match:||Landing gear failure on landing, Accident of aircraft Fokker MK-100, registration I-ALPL, at Barcelona Airport (Barcelona), on 7 November 1999|
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