Irish investigators have credited a cabin service supervisor with containing a serious pressurisation incident which developed after a Ryanair Boeing 737-800 suffered a tail-strike on take-off from Dublin.
Despite realising that something had occurred during rotation, the crew allowed the aircraft to continue climbing while they considered the situation. By the time the pilots had identified a probable tail-strike, and started the necessary checklist procedure, the aircraft had reached flight level 120.
Part of the checklist involved activating the pressurisation outflow valve, but the aircraft's relatively high altitude meant this resulted in a serious loss of cabin pressure.
"Crucially the flight crew did not consider fully the consequences of manually opening the outflow valve," says the Irish Air Accident Investigation Unit, adding that the passenger oxygen system did not deploy automatically because the aircraft had levelled below 14,000ft.
"It was apparent that the [cabin service supervisor] alone quickly realised the seriousness of the situation when the cabin was depressurised and took the correct action in immediately informing the flight crew."
The supervisor tried contacting the pilots on the intercom but, because the crew was putting on oxygen masks, they did not hear her. She resorted to banging on the cockpit door in order to alert the pilots to the depressurisation and the lack of passenger masks.
After this call the flight crew deployed the passenger oxygen system manually, although the investigators note that three service units - providing masks for nine seats - failed to open.
"The initial event on this flight, the tail-strike with the runway, was not a serious event in itself," says the AAIU. "However, the chain of events following the tail-strike led to this occurrence becoming a serious incident where many of the passengers were anxious and upset."
In their final report, the investigators state that the cabin supervisor's intervention was a "significant contributing factor" in resolving the crisis.
The aircraft, serial number 33632, was only a few months old at the time of the incident on 11 September last year. It returned to Dublin and landed safely.
Ryanair has since introduced a number of changes including an amended take-off brief, clarity over communication procedures between cabin and cockpit, and better training regarding tail-strike avoidance and depressurisation awareness.
Airline profile: Ryanair
Source: Air Transport Intelligence news
