Eurowings CRJ9 at Geneva on Dec 10th 2015, odour in cabin and cockpit

Last Update: July 18, 2018 / 11:41:46 GMT/Zulu time

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Photo of Eurowings D-ACNP, Canadair CL-600 Regional Jet CRJ-705 — Eurowings D-ACNP, Canadair CL-600 Regional Jet CRJ-705 (Photo credit: c38astra / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Dec 10, 2015

Classification
Incident

Airline
Eurowings

Flight number
EW-1741

Departure
Geneva, Switzerland

Destination
Dusseldorf, Germany

Aircraft Registration
D-ACNP

Aircraft Type
Canadair CL-600 Regional Jet CRJ-705

ICAO Type Designator
CRJ9

A Eurowings Canadair CRJ-900, registration D-ACNP performing flight EW-1741 from Geneva (Switzerland) to Dusseldorf (Germany) with 44 passengers and 4 crew, was climbing through FL280 out of Geneva when the crew donned their oxygen masks reporting an odour in cabin and cockpit and decided to return to Geneva, where the aircraft landed safely on runway 23 about 35 minutes after departure.

On Dec 28th 2015 Switzerland's SUST reported a stale smell was already noticed in the cockpit. After takeoff the smell persisted and became noticeable also in the cabin prompting the flight crew to don their oxygen masks and return to Geneva. The occurrence was rated a serious incident, an investigation has been opened.

On Jul 18th 2018 the SUST released their final summary report in German concluding the probable causes of the serious incident were:

Based on various examinations it appears obvious that strong pollution of the filter cartridges of the air conditioning systems were connected to the unusual odour in cockpit and cabin. It is probable that due to the low air throughput through the filters the bearings of the re-circulation fans heated up signficantly and distributed an irritating odour.

The fact that the MDC (Maintenance Diagnostic Computer) did not register a status message regarding the re-circulation fans during the incident flight and that the crew did not mention such a status message, permits to conclude that the thermo-switches of motors of the re-circulation fans did not trigger. Why the thermo switches did not trigger and thus did not automatically shut down the re-circulation fans, could not be established.

The decision by the crew to abort the flight and return to Geneva was safety conscious.

Following the appearance of the odour several members of the crew felt adverse effects on their health and performance. It is thus hardly understandable that one of the flight crew members did not don her oxygen mask. In dealing with potentially toxic substances it needs to be considered that such substances do not affect all individuums in the same way. Even if the own current well-being does not seem to be affected, it is hardly sensible to not use protective measures until first adverse effects set in.

The SUST reported that the first officer (38, ATPL, 4,023 hours total, 3,064 hours on type) noticed some odour in the cockpit while the aircraft taxied out for departure. Both flight crew identified the odour as one that could occasionally occur in connection with a flight, the decision was taken to continue and the aircraft departed.

During the climb cabin crew began to notice the odour too, the first officer felt increasingly affected by the odour and donned his oxygen masks. After levelling off at FL280 and consulting with the cabin crew the flight crew decided to return to Geneva and declared PAN PAN. The captain (54, ATPL, 9,790 hours total, 6,288 hours on type) maneouvered the aircraft onto final approach, the first officer removed his oxygen mask, and performed a safe landing on Geneva's runway 23 about 36 minutes after departure. The odour was still present, the crew described the odour as possible oil smell.

The SUST reported during the climb the first officer increasingly felt head ache, tickling in the throat, dizziness and difficulties to concentrate. He therefore donned his oxygen masks but removed it before landing. Several minutes after landing the first officer still reported being dizzy and not fit to fly.

Both members of the cabin crew reported a tingling feel on their lips and a furred tongue as result of the odour. The odour was unpleasant, there was no observation of smoke or mist.

The captain noticed the odour on her side of the cockpit, too, however did not feel affected by the odour and thus did not don her oxygen mask.

Most of the passengers did not notice the odour.

The SUST reported that immediately after the event it was not possible to perform a medical evaluation. In later examinations it was not possible to determine whether the crew members were exposed to toxic substances.

The crew described the communication with the emergency services in Geneva as problematic because the emergency services only spoke French.

Examination of the aircraft did not find any oil contamination on either engine and associated bleed air systems. The odour could be observed from the right hand air conditioning system, the controller for the left air conditioning system produced an error (which the manufacturer described as nuisance alert). The right air conditioning system was set inactive under minimum equipment list requirements. The aircraft positioned, without passengers, to Dusseldorf without another odour event. In Dusseldorf the aircraft underwent various tests including for oil contamination of both engines and APU, contamination of both bleed air and air conditioning systems. Both filter cartridges of the air conditioning systems showed strong pollution and were replaced. None of the systems recorded a fault with the re-circulation fans.