While Pratt & Whitney (P&W) said it is working with IndiGo and GoAir as well as the regulator over the issues, "boroscopic inspection" of the engines has already started.
The Directorate General of Civil Aviation (DGCA) has directed the airlines to carry out inspection after taking serious note of recent incidents, where some IndiGo and GoAir flights had to make emergency landings due to engine issues.
As many as 21 A320 neo planes -- that are using P&W engines -- would be examined and the exercise is expected to be completed in the next two weeks, a senior DGCA official said.
In case, the boroscopic inspection is unsatisfactory, the regulator has said the engine operation should be as per manufacturer's recommendation subject to certain conditions.
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However, recommendation below 375 hours shall not be accepted, the official said.
The examination of the engines is being done using boroscope -- an optical device that is used for inspecting parts that are generally inaccessible. Hence, the exercise is called boroscopic examination.
In a statement, P&W said it is supporting GoAir and IndiGo to assess the situation and minimise any disruption.
"The issues are still under review, so it would be premature to speculate on the cause. We are working closely with our customers and our suppliers in order to address and resolve these issues quickly," it noted.
After carrying out preliminary probes into incidents involving P&W engine-powered neo planes, the official said a frequent issue has been with one of the bearings in the engine apart from those related to combustion system.
According to the official, the engine maker is likely to fix the problems by September this year.
Even though DGCA carries out inspection of planes routinely as part of ensuring overall safety, it is rare for the regulator to order detailed examination of a particular class of aircraft and a specific engine.
Globally, 13 P&W engines were removed prematurely due to "combustion chamber distress", while the number of removals on account of "3 bearing distress" stood at 28. Only engine was removed due to "main gear box" failure during this period, as per data available with DGCA till February 24.