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| Date: | Tuesday 11 July 2023 |
| Time: | 18:06 |
| Type: |  Airbus A330-343 |
| Owner/operator: | Swiss International Air Lines |
| Registration: | HB-JHL |
| MSN: | 1290 |
| Year of manufacture: | 2012 |
| Engine model: | Rolls-Royce Trent 772-B60 |
| Fatalities: | Fatalities: 0 / Occupants: 235 |
| Other fatalities: | 0 |
| Aircraft damage: | None |
| Category: | Serious incident |
| Location: | over English Channel -
 United Kingdom
|
| Phase: | En route |
| Nature: | Passenger - Scheduled |
| Departure airport: | Zürich-Kloten Airport (ZRH/LSZH) |
| Newark-Liberty International Airport, NJ (EWR/KEWR) | |
| Investigating agency: | STSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
Swiss International Air Lines flight LX18, an Airbus A330-343, was en route at FL340 over southern England when an unusual smell caused the crew to declare an emergency. The flight diverted to Paris-CDG Airport, France, where it landed at 17:53 UTC.
The aircraft had departed from Zurich Airport (LSZH) at 15:54 UTC on 11 July 2023. On board the
aircraft, which was scheduled to fly to Newark Liberty International Airport (KEWR)
with flight number LX18, were 2 pilots, 10 cabin crew members and 223 passengers.
During taxiing to the runway for departure from Zurich Airport (ZRH), the cockpit crew noticed a slight, unusual smell in the cockpit, which reminded them of heated asphalt or tarred road surface. As the outside temperature was 38 °C, the pilots suspected that this smell was coming from outside.
The takeoff from runway 16 in Zurich took place at 16:07 UTC. As usual, the two air conditioning packs were switched off. When Air Conditioning Pack 2 was turned on during the climb, the cockpit crew again noticed a stronger smell of "dirty socks or damp cellar", so the commander switched off Air Conditioning Pack 2, after which the smell disappeared. After around five minutes, the commander activated Air Conditioning Pack 2 again; this time, no unusual smell was noticeable.
The commander subsequently asked the two senior cabin crew members, and the remaining eight flight attendants, whether they had also noticed an unusual smell. Various FAs replied in the affirmative, stating that the smell was particularly noticeable during the initial climb but then dissipated almost completely. During the rest of the flight, several FAs began to complain of a distinct burning sensation and irritation of the eyes, as well as headaches. It is not known whether passengers had similar perceptions.
At this time, the aircraft HB-JHL was over the English Channel at flight level (FL) 340. Due to the emerging physical complaints of some cabin crew members, the cockpit crew decided to return to Zurich Airport. At 17:05 UTC, they issued an urgency message (Pan-Pan) and began a descent after they had put on their oxygen masks. At the same time, the pilots carried out the abnormal checklist in the Quick Reference Handbook for smoke and fumes, during which Air Conditioning Pack 2 was also switched off.
During this phase, the two senior cabin crew members, together with the rest of the cabin crew, decided to put on the smoke hoods, or Protective Breathing Equipment (PBE), to protect themselves.
Due to deteriorating weather conditions in Zurich, the cockpit crew decided to make an alternative landing at the nearby Paris-Charles-de-Gaulle Airport (LFPG), where the aircraft HB-JHL landed uneventfully after almost two hours of flight time.
Causes
In the serious incident, an unusual smell developed in the aircraft cabin during the cruise flight, the cause of which could not be determined. This prompted the cockpit crew to put on their oxygen masks and several cabin crew members to use Protective Breathing Equipment (PBE). Several cabin crew members reported significant difficulties in using the PBE, both in unpacking, unfolding, putting on and activating the units and in their subsequent use. In addition, several PBE units exhibited technical defects and were therefore not or only partially functional. This represents a significant safety risk.
The following factors contributed to the serious incident:
The recurring maintenance measures were inadequate, which is why the existing defects in the PBE units remained undetected.
The crew members were trained exclusively with dummy PBE provided for training purposes, which differs considerably from the real PBE used in an emergency. As a result, the crew members were unaware of various difficulties when using the PBE.
The technical design of the PBE was such that trained cabin crew members were unable to activate the PBE within a reasonable amount of time. The time required was several times longer than that specified in the certification criteria. In addition, communication was severely impaired when the PBE was in use.
Accident investigation:
 |
|
Sources:
https://www.20min.ch/story/notfall-an-bord-swiss-flug-nach-new-york-kehrt-um-252015476904
https://www.flightradar24.com/data/aircraft/hb-jhl#3117b44c
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 12-Jul-2023 19:16 | harro | Added |
| 11-Oct-2023 11:30 | harro | Updated |
| 04-Jun-2025 12:58 | ASN | Updated [Total occupants, Location, Narrative, Accident report, ] |
| 04-Jun-2025 14:00 | ASN | Updated [Narrative, ] |
| 06-Jun-2025 00:58 | Justanormalperson | Updated |
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