Created Thursday, Mar 25th 2021 14:08Z, last updated Thursday, Mar 25th 2021 17:49Z
A Swiss International Airlines Bombardier C-Series CS-100, registration HB-JBC performing flight
LX-647 from Paris Charles de Gaulle (France) to Zurich (Switzerland) with 112 passengers and 5 crew, was on approach to Zurich when the crew reported they had needed to shut an engine (PW1524) down. The aircraft continued for a safe landing on runway 14, vacated the runway and stopped for an inspection by emergency services before taxiing to the apron.
The occurrence aircraft was still on the ground in Zurich about 111 hours after landing.
On Nov 27th 2018 Switzerland's SUST reported the occurrence has been rated a serious incident and is being investigated. The crew had shut the left hand engine down due to loss of oil.
On Mar 25th 2021 the SUST released their factual final report in German only (Editorial note: to serve the purpose of global prevention of the repeat of causes leading to an occurrence an additional timely release of all occurrence reports in the only world spanning aviation language English would be necessary, a German only release does not achieve this purpose as set by ICAO annex 13 and just forces many aviators to waste much more time and effort each in trying to understand the circumstances leading to the occurrence. Aviators operating internationally are required to read/speak English besides their local language, investigators need to be able to read/write/speak English to communicate with their counterparts all around the globe).
The report concludes the probable cause of the serious incident was:
The loss of oil at the O-ring at the Fuel-Oil-Cooler was caused by a technical cause that can be corrected by application of Service Bulletins PW 79-00-0012 and PW 79-00-0013 by the engine manufacturer.
The SUST reasons that because of this finding no further relevant findings will be made and thus terminates the investigation with this brief final summary report.
The SUST reported the aircraft was climbing through FL200 out of Paris when the crew received warning for low oil quantity followed by another warning for low oil pressure for the left hand engine. The crew followed the relevant checklists, shut the engine down and continued to Zurich.
The oil leak was caused by a defective O-Ring sealing at the fuel-oil-cooler.
Before the occurrence the engine manufacturer had already released Service Bulletin PW 79-00-0011, which suggested to replace the fuel oil cooler with a newer one which has a longer thread and higher torque at the related connector. The modification was not deemed urgent by the engine manufacturer and had not been applied to HB-JBC.
Following the occurrence the engine manufacturer released another service bulletin PW 79-00-0012 which required periodic inspections of the oil-fuel-cooler with heightened urgency. The inspection of the fleet of Swiss subsequently revealed two further affected fuel-oil-coolers which were replaced.
On Mar 29th 2019 the engine manufacturer released Service Bulletin PW 79-00-0013 which required the replacement of the affected oil line. On Mar 27th 2020 the FAA adopted both service bulletins PW 79-00-0012 and PW 79-00-0013 in their Airoworthiness Directive AD-2020-04-01. This AD was subsequently also adopted by EASA.
Related Flight:
LX647,
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