The preliminary report, published yesterday, found the unit, which had not locked properly into place, could have taken the weight of one passenger without negative consequences.
However when three people stood on the section in question, it slid “rapidly downwards” with a loud noise, trapping and causing serious injury to the leg of a female passenger.
The incident occurred on June 27 last after the aircraft, a Boeing 737-800, had parked at Dublin Airport, following a flight from Krakow. During disembarkation from the rear door the first three passengers emerged from the aircraft onto the mobile air stairs unit. The stairs then partially collapsed.
Investigators for the Air Accident Investigation Unit (AAIU) of the Department of Transport, found the locking mechanism on the unit was creating a “false” lock condition which was sufficient to allow one person to stand on the sliding stair without adverse consequence, but not three.
The air stairs is a telescopic unit, comprising a fixed step section and a hydraulically actuated, sliding step section, which allows the air stairs to be adjusted for door heights. Investigators found part of the locking mechanism to be “unserviceable and incapable of engaging”.
The air stairs unit was delivered new to Ryanair in September 2008.
The investigators made a series of recommendations including airline personnel “confirm and crosscheck the correct engagement” of the locking mechanism. A spokesperson for Ryanair, which has responsibility for the safety of passengers disembarking the plane via the mobile stairs unit, said they had already compiled with the recommendations of the AAIU report “to ensure this extremely rare incident will never re-occur”.