Tata-Singapore airlines joint venture Air Vistara appears to be going through more engine trouble in its Airbus Neo planes than it would like to admit.
The A-320 Neo operator has been reporting multiple problems in its CFM Leap I engines, four of which have already been replaced after induction a year ago. Another two are awaiting replacement following problems in the turbines of the engines.
Two days ago, the Delhi-Bangalore flight could not take off because the engine would not start. Apologising to passengers on Twitter, Vistara had admitted that "Though it is a very new aircraft, there is a technical glitch that has caused the delay".
Sources in the airlines said, "Engine problem in Vistara aircraft have been reported for HPT Stage II and four of these have already been replaced in the past one year. What we are seeing now are problems in HPT Stage I, which have not been reported to the DGCA (Directorate General of Civil Aviation) as yet. There are problems in the turbine as the coating is coming off. This can lead to cracks in the turbines. Two engines out of 14 are slotted for a change including the one used in the aircraft on the Delhi-Bangalore route".
Similar problems have been reported with engines fitted in Air India aircraft as well with at least six being replaced in one year.
HPT Stage 1 engines completed 200 fight cycles recently after being inducted around a year ago. During routine maintenance, the turbine damage was detected. What's alarming is that trouble is being spotted early in the engine's life. While Airbus recommends a service check first at 200 flight cycles and then at 1600, this is now being changed. Engines are to be checked more frequently at 500 cycles.
It is not just problems with turbine coating eroding, leading to cracks developing in the turbine, but multiple problems, sources said.
The Delhi-Bangalore flight delay was because the engine did not start due to the exhaust gas temperatures rising.
A Vistara spokesperson said: "There have been no safety issues or in-flight shutdowns on our A-320 Neo engines. Initial glitches can occur from time to time on any new engine, aircraft, and are addressed as per routine process with the manufacturers in coordination with all regulators -DGCA, EASA, FAA. There is no safety implication whatsoever."
The DGCA has already grounded several aircraft using the Pratt and Whitney engines of a particular series.
Vistara had selected CFM International's LEAP-1A engine for the aircraft along with Air India. CFM Leap and P&W are the two companies that manufacture Neo engines for Airbus. P&W users, GoAir and Indigo, have reported inflight shutdowns, but not Vistara or Air India.
Aviation regulator DGCA had in March this year grounded 11 A320 neo aircraft powered by a particular series of Pratt & Whitney engines following instances of engine failures during flights. While eight of these planes are operated by IndiGo, three of them belonged to GoAir.
The decision was announced within hours of an Indigo A320 neo aircraft being forced to make an emergency landing at the Ahmedabad airport due to engine failure in mid-air.
The DGCA said, A320 neos fitted with PW1100 engines beyond ESN 450 have been grounded with immediate effect due to safety reasons.
Both IndiGo and GoAir had also been told not to refit these engines, which were spare with them in their inventory. The move had led to a major dislocation of IndiGo flights at the time.
The European Aviation Safety Agency European (EASA) had on February 9 issued an emergency airworthiness directive for A-320 Neos fitted with PW1100 engines from serial number 450 and beyond due to some occurrences of aborted take-off and in-flight shut down of these engines. Immediately after this three IndiGo planes were grounded in India as these planes had both engines belonging to this category.