The co-pilot of the BAe146-300 reported that he noticed both
cockpit side windows were open as he entered the flight deck to
commence his pre-flight preparations and almost immediately
detected the presence of fumes. He stated that these fumes had a
distinctive odour that he recognised as being consistent with the
contamination of the cabin air supply by lubricating oil from the
aircraft's engines. This typically occurs when a faulty bearing
seal allows lubricating oil to escape and contaminates one of the
sources of cabin air for the aircraft.
The auxiliary power unit (APU) was operating and air
conditioning Pack 1 and 2 were supplying air to the flight deck and
passenger cabin. As Pack 1 supplies most of the air to the flight
deck and because fumes were not apparent in the passenger cabin,
the co-pilot immediately suspected that the contamination was
associated with Pack 1. He de-selected Pack 1 and noticed an
immediate improvement to the quality of the air.
The co-pilot briefed the pilot in command of these observations
when he arrived on the flight deck. The crew used engine bleed air
to provide cabin air conditioning as the aircraft taxied for
takeoff and Pack 1 remained de-selected. This was on the basis of
the tailwind conditions encountered while taxiing, to reduce the
possibility of ingesting fumes from the APU's exhaust into the
aircraft cabin and the co-pilot's observations of air quality from
Pack 1. The takeoff was performed with all air conditioning packs
selected off and number-4 engine supplying bleed air for
pressurisation control of the aircraft cabin.
The co-pilot was the handling pilot for the sector from Perth to
Karratha. After takeoff, the crew selected engine bleed air sources
from all engines and Pack 1 and 2 were used to provide air
conditioning to the passenger cabin and flight deck. No fumes were
evident in either the passenger cabin or the flight deck and the
flight proceeded normally.
About 10 minutes prior to the top of descent, the co-pilot
recalled starting to experience symptoms of a headache. He was able
to continue his duties as handling pilot and completed the descent
to the Karratha circuit area. The aircraft was on final approach to
land, when strong oil-type fumes were again detected on the flight
deck. As the aircraft cabin had already stabilised at sea-level
atmospheric pressure and the source of fumes appeared to be either
the air conditioning packs or one of the engine bleed air supplies,
all air conditioning packs and all sources of engine bleed air were
selected off. The intensity of the fumes quickly dissipated and the
co-pilot completed the landing. Fumes were not detected in the
passenger cabin by any of the flight attendants. The co-pilot
reported that supplemental oxygen was not used on this occasion due
to the critical phase of flight (short final approach to land) and
the prompt action taken to isolate the source of fumes.
During the taxi to the passenger terminal, the co-pilot became
aware that he was experiencing symptoms of an unusually strong
headache, nausea and irritated eyes, nose and throat. His symptoms
quickly improved as he conducted the external turnaround duties and
he felt capable of performing his duties on the return sector as
pilot not flying.
The pilot in command was satisfied that the source of fumes
experienced on short final was associated with contamination of the
cabin air supply by engine lubricating oil. The return flight was
conducted without using APU air and with Pack 1 de-selected to
minimise the possible recurrence of fume contamination. The flight
was completed without incident.
Subsequent to the incident, the co-pilot recalled that during
the outbound sector his bottled drinking water, which had been
poured and left standing in his cup, had acquired a rank swampy,
slightly metallic taste. The pilot in command was also reported to
have made a similar comment about the taste of his drinking water.
The cups were resting in the flight deck cup holders adjacent to
the air outlet vents. This was noticed prior to the co-pilot
reporting symptoms of a headache and fresh cups of water from the
bottle tasted normal with no apparent sign of contamination. The
ATSB were not able to test the water for contaminants as it had
been discarded following the flight.
Following entry of the fume report in the aircraft's defect log,
company engineering personnel applied the requirements of
Airworthiness Directive AD BAe 146/86, issued 30 March 2001 that
required inspection of various components associated with the
aircraft's cabin air supply. This inspection revealed no apparent
defects or source of contamination to the cabin air.
The operator received subsequent Operating Crew Reports
associated with poor cabin air quality on 23 and 26 October 2002.
The aircraft commenced a period of heavy maintenance on 28 October
2002. During this maintenance the APU was removed from the
aircraft, cleaned, inspected (with nil defects found) and refitted.
Air conditioning Pack 1 was also cleaned. The operator received
subsequent reports of flight deck odours with respect to this
aircraft on 5 and 8 December 2002 and the requirements of the
Airworthiness Directive were again applied. On this occasion the
inspections revealed slight leakage of engine lubricating oil from
a bearing seal on the number-4 engine.
