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SriLankan says neo flights restricted because of engine problems
SriLankan Airlines (SLA) is flying all but one of its Airbus ‘neo’ fleet within an hour’s range of airports suitable for emergency landings as its Engineering Department has noticed a deterioration in “engine gas temperature” margins of certain engines and is working with the manufacturer to rectify the problem, the company said.
“These decisions are taken by the Engineering Department of the organisation as part of their primary role to dispatch aircraft that can complete the mission and ensure that the exemplary safety standards set by the airline are met,” the airline said in a statement issued to the Sunday Times. “SLA Engineering is working closely with CFMI {the engine manufacturer} to ensure that a software upgrade and some hardware replacements are carried out, after which EDTO [Extended Diversion Time Operations] will be restored, on an individual basis, to selected aircraft.”
The Sunday Times has for several weeks reported on issues related to the Extended Twin-engine Operations (ETOPS) certification granted to SriLankan’s A320/321 neo fleet by the Civil Aviation Authority of Sri Lanka (CAASL). Approval allows these twin-engine aircraft to fly at least 90 minutes outside the range of airports suitable for emergency landings.
But the airline lost ETOPS certification in January after its Maintenance Department released one of the planes (registration 4R-ANE) for use despite having detected debris in the oil monitoring system of an engine. Consequently, the A321 neo flying as UL 898 to Hong Kong on January 21, 2018, was forced to shut down the engine in question and divert to Bangkok on a single engine. The CAASL carried out an investigation and immediately withdrew ETOPS certification.
On May 11, CAASL restored ETOPS certification after weeks of discussion and inspection. A spokesman for the regulator said the airline had addressed its concerns. Without availing itself of the facility, however, SriLankan continues to operate just one of its five Airbus neos as an ETOPS flight. This means the other aircraft spend extra time in the air to ensure that they are always within 60 minutes of an emergency or diversion airport. They burn up extra fuel while passenger travel time greatly increases.
SriLankan said this week that the reason was due to “manufacturing deficiencies”. It was not immediately clear whether the maker of the engines—CFM International Jet Engines (CMFI)—or the lessor—AerCap—will compensate SriLankan for losses sustained; and whether such contingencies are written into the relevant agreements.
“ETOPS (Extended Twin-engine Operations) or more correctly EDTO (Extended Diversion Time Operations) refer to aircraft that fly further than a designated distance from a suitable airport. All aircraft are certified to fly up to 60 minutes (about 700 to 1000 km depending on the aircraft) from a suitable airport,” the statement said. “In the case of twin-engine aircraft, to fly further than this from a suitable airport, the aircraft must be certified for EDTO by both the manufacturer and the regulator.”
In the case of the A320/321 fitted with CFMI LEAP engines, the manufacturer has been granted EDTO approval. The CAASL also granted 90 minutes EDTO approval but withdrew this in January. Since then, it has been approved once again. This approval is granted to a combination of airframe plus engine, not to individual aircraft.
“However, the operator (SriLankan Airlines) in coordination with the manufacturer (CFMI), have a cutting-edge engine monitoring programme that relies on real-time information sent via satellite link to CFMI’s central computers,” it continued. “Using this information, each individual engine is constantly monitored and all engine parameters are closely scrutinised, to ensure that safety margins are strictly observed.”
“Using these advanced techniques, SLA Engineering has noticed a deterioration in the Engine Gas Temperature (EGT) margins of certain individual engines,” it said. “Engine EGT margin is a key parameter for EDTO operation and the decline on some engines is due to some manufacturing deficiencies.”
“These decisions are taken by the engineering department of the organisation as part of their primary role to dispatch aircraft that can complete the mission and ensure that the exemplary safety standards set by the airline are met,” it explained. “SLA Engineering is working closely with CFMI to ensure that a software upgrade and some hardware replacements are carried out, after which EDTO will be restored, on an individual basis, to selected aircraft.”
The airline emphasised that its primary focus is safety and that it is committed to ensuring the whole fleet “exceeds the required safety standards and we will not compromise this in any way”.