History of the Flight
Shortly after takeoff from Edinburgh, while climbing through approximately FL80, the amber 'SMOKE' caption illuminated on the Central Warning Panel, indicating smoke detection in either the toilet compartment or the baggage hold. A strong smell of fumes in the cockpit prompted the flight crew to don oxygen masks. The climb was stopped and a diversion to Glasgow was initiated. The captain briefed the Senior Cabin Crew Member to check the toilet compartment, while the flight crew actioned the 'Fire or Smoke within Fuselage' emergency checklist. The 'SMOKE' caption extinguished after about two minutes. The SCCM reported a light mist in the toilet compartment and that the first four overhead lockers felt warmer than others, but no other signs of smoke or fire. A priority approach and uneventful landing were made at Glasgow. The aircraft was stopped clear of the runway while the crew contacted the airport fire service, then taxied to stand for normal disembarkation with fire service attendance.
Engineering Investigation
Troubleshooting included operational tests of cockpit and cabin lighting, electronic flight instrument and weather radar displays. Checks for burnt wiring in the flight deck, avionic bay, and cabin service panels revealed nothing. Smoke detectors in the toilet and baggage bay were tested satisfactorily. Engine ground runs and bleed air pack tests over their full range showed normal functions and indications. A review of the aircraft technical log found no evidence of excessive engine oil consumption or overfilling. No defect could be identified, and the aircraft was returned to service.
On 11 February, after four further sectors, the flight crew reported an indefinable musty smell, similar to curing adhesive, in the cockpit and cabin. Investigation linked the smell to the No 2 (right hand) bleed air pack; the smell disappeared when the No 1 pack was used alone. Maintenance Manual procedure 71-05-04 for 'Smoke Odour/Oil Mist in Cabin' traced the fault to an accumulation of oil in the No 2 engine LP compressor inlet. The area was cleaned, but engine ground runs caused the smell and oil leak to recur. The aircraft was ferried to the airline's maintenance base with the No 2 engine bleed switched off. The No 2 engine (serial number 124236) was removed and returned to the manufacturer for investigation.
The reason for the first four overhead lockers being warmer than others could not be established, but it does not appear to have been associated with the cause of the incident.