Launched in December 2010, Airbus A320neo (new engine option) is one of the fastest-selling aircraft in history. With a pending order book of 6,005 from 98 customers, the aircraft has overtaken its closest competitor in the narrow-body segment - Boeing 737 Max - which was launched a few months later. But with a series of issues with the engine suppliers - Pratt & Whitney (P&W) and CFM International - the future of A320neo seems to have been jeopradised. Take P&W, for instance. Within two years of its commercial launch, the engine has been hurtling from one problem to another. Last year, its PW1100G engine - based on geared turbofan - developed snags, including distress in a carbon-air seal for No. 3 bearing and degradation of combustion chambers. The company later announced that it had found "fixes" for those issues. In February, the European agency EASA raised a red-flag with a particular series of P&W engines after several instances of engine in-flight shut-down and aborted take-offs were reported on certain Airbus A320neo family planes. EASA had asked airlines to restrict using engines of the same series on a single aircraft. It resulted in P&W halting the deliveries of new engines till the issue is rectified. On Monday, a mid-air engine failure forced an IndiGo flight bound for Lucknow to return to Ahmedabad. Following which, aviation regulator DGCA asked GoAir and IndiGo to ground their some 11 planes that are equipped with "problematic" P&W engines. While teething problems are common for any new engine technology, the persistent issues with P&W engines raised serious doubts over its trustworthiness over a longer period. In a conversation with Business Today last year, Palash Roy Chowdhury, managing director (India) for P&W had said that "the typical lifecycle of GFT technology is about 30 years, and the technology has just finished its first year. There's a continuous improvement process for our programmes." However, there's no major respite for airlines -- and Airbus - even if they opt for P&W's alternative - CFM's Leap-1A engine which directly competes with PW1100G. Engine maker CFM is co-owned by General Electric and France's Safran. So far, Leap-1A has a relatively smoother ride than PW1100G. Last year, there were quality problems with a turbine disc of Leap-1A. An additional problem with the premature loss of coating used on a part inside the A320neo version led to Safran setting aside about $58 million to troubleshoot in-service engines. State-run Air India too deferred the delivery of one A320neo powered by CFM engine last September. As compared to the previous narrow-body jets from Airbus, A320neo is more efficient - consuming 15 per cent less fuel, have lower CO2 emissions and significantly reduced noise footprint. These qualities attracted airlines across the world to introduce A320neos in their fleet, including 574 orders from GoAir and IndiGo. With problems with two key engine suppliers, the A320neo turning out to be an albatross around the airlines' neck.