IndiGo sets 30,000 feet altitude limit for Airbus A320neos to reduce engine strain

IndiGo has asked its pilots to fly snag-hit A320neo planes at a lower altitude, 30,000 feet, and not the usual 36,000 feet, to reduce strain on engines even though it will mean higher fuel burn. GoAir CEO Wolfgang Prock-Schauer said in an interview in February that Pratt & Whitney “will support us properly with spare engines and other support needs to be there so we can overcome the initial phase and don’t have any flight disruptions".

A Pratt & Whitney spokesman said it has no comment on the subject.

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Earlier this month, the engine maker said there were no safety issues in the planes and replacement engines were being sent to India when required. Still, the Directorate General of Civil Aviation (DGCA) has asked IndiGo and GoAir to increase surveillance of these planes, besides specifying other restrictions on when and where to fly them.

In January, an IndiGo flight had a so-called rejected take-off at Mumbai. In February, a GoAir flight from Delhi had to return to the airport after an engine fire 15 minutes into the flight. In the same month, a GoAir flight had to make an emergency landing and an IndiGo flight had to fly minus passengers to Delhi from Baroda.

Spokespersons for GoAir and IndiGo declined to comment for this story.

Analysts say the two airlines are facing teething troubles that early buyers of new aircraft do. They point to Air India’s troubles with Boeing’s Dreamliner. Usually, such problems are sorted out within the first two years of a new aircraft being launched.

In this case too, “technical issues will be sorted out in one-and-a-half years", Prock-Schauer said.

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IndiGo, which was the launch customer for the A320neo, has about 411 planes on order; it has so far inducted 19 in its 131-plane fleet. GoAir flies less than half-a-dozen of them and has about 140 on order. The planes, powered by fuel-efficient engines, are key to both airlines’ low cost model.

On 21 March, Ashim Mittra, vice-president (flight operations), IndiGo, said in a note to pilots that Pratt & Whitney had proposed limiting the altitude of flying to 30,000 feet for A320neo planes to avoid a possible glitch in the engine lubrication system and that, effective 22 March, IndiGo had decided to adopt the recommendation. Mint has seen a copy of the note. Since flying at lower altitudes consumes more fuel, the note asked pilots to fuel up accordingly.

Aviation analyst Mohan Ranganathan and former director general of civil aviation Kanu Gohain said it was rare for an airline to place such altitude restrictions.

Publicly known technical snags in the Neos include erroneous warnings to the pilot, longer start-up times, issues with the combustor chamber lining, oil seal failures and so-called oil chip detected warnings.

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“Pratt and Whitney has constantly been analysing other teething problems that have emerged during operations," Mittra said in his note to pilots.

Earlier this month, top Pratt & Whitney executives met DGCA officials to update them on the engine issues.

Former DGCA chief Gohain said more inspections would help.

“Whenever there are repeated engine issues you increase the frequency of inspections so that you can detect the internal distress of the engine earlier before it fails," he said.