SriLankan Airlines lost certification to operate its new A320neo and A321neo aircraft for more than an hour outside the range of airports suitable for emergency landings 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.
As a result, the A321neo aircraft 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 Civil Aviation Authority of Sri Lanka (CAASL) investigated and immediately withdrew certification granted to the airline “to conduct A320/321 aircraft on ETOPs [Extended-range Twin-engine Operational Performance Standards] with 90 minutes diversion time”, documents obtained by the Sunday Times under the Right to Information (RTI) Act show. The safety lapse is being treated by the regulator as very serious.
Without ETOPS approval, a flight must always be within 60 minutes of an emergency or diversion airport. With certification, however, it may fly longer–in the case of the A320-321neos, at least 90 minutes–outside the range of a suitable landing area. The suspension means that flights to such destinations as Hong Kong, Bangkok and Canton, for which the A320-321neos are used, clock additional flying times of at least one-and-a-half hours (both ways) as their routes are adjusted to ensure they comply with the 60 minutes rule. Five aircraft have been affected. Recently, the airline changed the plane on the Canton route to A330.
Without ETOPS certification, the aircraft also have to carry about 2000 extra kilograms of fuel. In addition to competitiveness, crew productivity takes a hit due to repeated delayed arrivals and departures. The Sunday Times reported last week that more than 900 SriLankan departures were late in February, with 280 of them leaving the airport over an hour behind. The February on-time performance of the airline was even worse than its January record when 840 departures were more than 15 minutes delayed (it was 911 in February), with 121 of them more than one hour behind.
Now, despite pleas from the embattled airline to restore the certification, CAASL is holding out till it is completely satisfied that maintenance standards pass muster. A fresh inspection last week did not engender sufficient confidence in the regulator to renew ETOPS approval, said H M C Nimalsiri, Director General of Civil Aviation (DGCA).
In a letter sent in January to the SriLankan Airlines Chairman, the DGCA said that CAASL did not find any cogent reason for the company’s Maintenance Department to have released the A321neo aircraft for service after detecting debris in the oil monitoring system of one engine (which has direct impact on flight safety) “without analysing the debris and taking appropriate preventive/corrective measures”.
His office was, therefore, of the firm belief that the engine in-flight shutdown (known as an IFSD in aviation) of the A321neo aircraft was totally preventable, had the Maintenance Department complied with approved procedures and was responsive enough to the timely application of sound maintenance principles and practices timely, Mr Nimalsiri says.
“At the same time, the incident also raises significant alarms in this office as to the competency, credibility and professionalism of SriLankan Maintenance Department as to the compliance with the regulations and application of sound aircraft maintenance practices for enhanced flight safety,” he warns.
Neo engines are electronically monitored, thereby allowing the manufacturer–in this case, the US-based CFM International (CFMI)–to flag potential issues. “When the engine manufacturer gets an alarm, they advise the operator what to do,” Mr Nimalsiri told the Sunday Times. “After the information is received, there should be a system to analyse and take immediate action.”
“In this instance, the manufacturer raised an urgent work card but the relevant department did not give due recognition to it and released the aircraft for commercial flights,” he held. A work card is a “tailored description of a maintenance task prepared from original documentation by a technical support office to facilitate the correct completion of that task by those assigned to complete it”.
As far back as January 5, 2018, CFMI alerted SriLankan of an issue in the oil debris monitoring system (ODMS) of the No 1 engine in the respective airplane. After further communication with the manufacturer, SriLankan Engineering issued a special work card dated January 8 requiring the Maintenance Department to investigate the ODMS sensor immediately.
However, SriLankan Maintenance only examined the engine on January 19, later stating that the “aircraft was not available due to engagement in commercial flights”, the DGCA notes in his letter to the SriLankan Chairman. Even then, the complete analysis process was not done before releasing the aircraft back to service.
The CAASL underscores “with serious concern” that debris was detected on the ODMS sensor during this inspection. And SriLankan Engineering had clearly called for an analysis of debris to determine the serviceability of the engine. Two days later, the engine had to be shut down. The CAASL inquiry found that “the event correlates to the previous ODMS sensor findings and engine bearing failure is a likelihood leading to the IFSD”. This caused the regulator to lose confidence in SriLankan’s maintenance arrangements, the DGCA told the Sunday Times.
To regain ETOPS certification, the operator must show they will not “do this type of loose, lackadaisical business again,” he said. “There must be a thorough audit to ensure a sound and reliable system in place.”
Meanwhile, SriLankan Airlines has claimed that the in-flight engine shutdown on January 21 was due to a manufacturing defect in the particular engine. This was published in an explanation written by Tyrone Navaratne, Senior Manger Engineering Quality, forwarded via Chief Executive Officer Suren Ratwatte to the Airline Pilots’ Guild of Sri Lanka.
The union wrote to the CEO asking whether certification was withdrawn “due to an inherent problem with the engine variant and, therefore, a manufacturer problem or due to negligence on the part of SriLankan Airlines”. This is despite the CAASL ruling that the IFSD was “not attributable to any manufacturing error but due to very poor maintenance practices of the operator”.
Mr Navaratne says that CFM International “has still not provided the reason for the failure”. However, he adds, “CFMI has increased the oversight and close monitoring of the other SriLankan Airlines neo engines”.
SriLankan Engineering Management has taken action to prevent another In-Flight Shutdown (IFSD), he asserts, while adding that reinstatement of ETOPS “is in the final stages, pending only the approval of documentation/procedures with CAASL”.
(Source: The Sunday Times – By Namini Wijedasa)