Thiruvananthapuram, Aug. 21: Two pilots of Jet Airways have been grounded, pending inquiry, after they landed a plane carrying over 140 passengers on the sixth or seventh attempt and with very little fuel to spare.

Aviation sources said the grounding did not presuppose guilt. But suggestions that the pilots have been suspended have triggered a debate on whether they are heroes or villains.

The controversy has also prompted some to air suspicions - unsubstantiated so far - whether some airlines try to cut corners by flying with fuel tanks that are not as full as they ought to be. Jet Airways has said its fuel uplift meets all regulatory requirements and flight planning includes "additional buffers to cater to unexpected scenarios".

The Jet flight was flying from Doha, the capital of Qatar, to Kochi, the commercial capital of Kerala, around 5.40am on Tuesday (August 18).

The pilots made three attempts to land in the airport on the outskirts of Kochi but could not do so because of weather-related poor visibility. The plane then headed to the state capital Thiruvananthapuram, a journey that takes around 20 minutes by air, made three more attempts and landed on the sixth, according to one passenger. Some sources said the landing took place on the seventh run.

By the time the Boeing landed, the fuel had gone into "reserve", according to sources. They said the plane had 270kg of fuel left at the time of landing against a mandatory requirement of 1,500kg. "Even 10 minutes of taxiing by a Boeing 737-800 burns 270kg of fuel," PTI quoted a source in the DGCA, the aviation regulator, as saying.

Reports also emerged that the pilot was asked to divert the plane to Bangalore but he headed to Thiruvananthapuram. But aviation sources discounted the claims, pointing out that the state capital was 20 minutes by air while Bangalore was 75 minutes away and the final call fell on the pilots.

It is not clear whether the plane had adequate fuel and it was burned up during the six or seven unscheduled attempts.

But Basil George, a former aeronautical chart editor at Lufthansa Systems, said in a Facebook post that regulations required the plane to have trip fuel plus 5 per cent of trip fuel as contingency fuel plus holding fuel for 30 minutes plus diversion fuel to another destination.

"In this case, they only had trip fuel + a bit of extra fuel," George posted. It was not clear whether he had based his conclusions on specific information or unattributed reports that were doing the rounds.

George felt that the pilots should not have made so many attempts to land in Kochi and should have headed to an alternative destination sooner.

Some passengers hailed one of the pilots, Manoj Kumar Ramawarrier, for "saving" the lives of those on board.

"I travelled same flight yesterday. Special thanks for pilot Mr Manoj Ramvariar,'' read a Facebook post by Prakash Mohan. "Thanks for all jet airways crew.... We safely reached home,'' he said in another post which also featured his ticket for the Doha-Kochi flight 9W 0555.

Ashique Basheer, another passenger, told The Telegraph: "I run a business in Qatar and had come to take my family, vacationing in Kerala, back to Doha. We were scheduled to land in Kochi at 5.40am. We reached on time but I saw there was fog outside and nothing was visible through the window. The flight made a first attempt to land but it could not. Soon there was the announcement that there was zero visibility. Then a second attempt was made, but that was unsuccessful too. Before the third attempt, the announcement said the flight may be diverted to a nearby airport if it failed to land in Kochi again.

"The flight failed to land again and was diverted, but we were not told to which airport we were travelling. I have been flying for the last seven years and recognised Thiruvananthapuram from above.... I feared the pilot may be trying to crashland on the sand (the airport is very close to a beach). But then it entered the airport and landed.''

Basheer added that the video clip on safety instructions, which is routinely shown on take-off, was played after the second attempt failed. "The crew, however, were composed. I saw them comforting a young girl who was panicking after the flight failed to land in Kochi.''

Unconfirmed reports said the instrument landing system at Thiruvananthapuram was faulty and this might have delayed the landing.

George, the former aviation official, also referred to the "unserviceable status of the instrument landing system" in his post and added: "I appreciate his piloting skill to land a plane in poor visibility without an instrument landing system.''

Jet Airways said that diversion was a precautionary measure in line with the standard operating safety procedure as the runway at Kochi was not visible because of the presence of low clouds.

"The flight landing with 141 guests was uneventful," the airline said.

"At Jet Airways, safety is of paramount importance, and to this end, planning of flight operations is conducted with a very high level of safety. This includes a fuel uplift that not only meets all regulatory requirements but also has additional buffers to cater to unexpected scenarios, including poor weather at the alternative airport. Since the matter is under investigation by the airline safety team, as also the DGCA, we are unable to comment any further on the matter."

Additional reporting by our Delhi Bureau