Description

On 17 November 2007 a Boeing 737-700 being operated by Virgin Blue on a scheduled passenger service from Coolangatta to Melbourne experienced a failure of the right hand engine bleed during the take off. The flight was continued but subsequently, during the climb in night IMC to FL350, the left air conditioning pack failure and an emergency descent followed with passenger oxygen masks deploying as cabin altitude exceeded 14000 feet. A diversion was made to Brisbane .

Investigation

An Investigation was carried out by the ATSB.

It was found that the initial fault has occurred below 80 KIAS during the take off roll. An attempt at reset after becoming airborne but when still below MSA was not successful and with APU air not available above FL170, it was initially decided to cruise at FL250, a lower level than planned. Once there, however, icing conditions were encountered and it was decided to continue the climb to FL350 so as to be able to cruise clear of cloud.

Then, at FL318 during the climb, about 135 nm south west of Coolangatta, the left air conditioning pack failed and an emergency descent was made to 10000 feet. During this descent, cabin altitude exceeded 14000 feet, which led to the passenger oxygen masks deploying automatically. Thereafter, the diversion to Brisbane was achieved by making a track reversal to an airport near to but larger than the departure airport.