Mumbai/Kolkata, Jun 17 (PTI) Troubles continued at Air India, which is facing the biggest crisis since Tata group bought the airline three and a half years back, with its flights to London and Paris on Tuesday being cancelled for varied reasons and a glitch forcing fliers on San Francisco-Mumbai flight to deplane during a stopover.

While Air India cancelled the Delhi-Paris flight after some problems were detected during pre-flight checks, its Ahmedabad-London one was cancelled due to unavailability of aircraft, the airline said.

Separately, Air India terminated its San Francisco-Mumbai flight at its scheduled stopover at Kolkata early on Tuesday morning after one of its engines developed a technical snag.

The disruptions came as investigators probe what caused a London-bound Air India flight to crash in Ahmedabad shortly after take-off on June 12, killing more than 270 people onboard and on the ground.

The incident dealt a severe blow to the airline and its owner Tata, which prides itself for producing luxury cars to salt and software as well as assembly of iPhone.

In a statement, Air India said flight AI143 from Delhi to Paris has been cancelled after "mandatory pre-flight checks identified an issue which is being presently addressed".

It did not detail the issue that came to light during pre-flight checks.

"However, in view of the flight coming under the restrictions on night operations at Paris Charles de Gaulle (CDG) airport, the said flight has been cancelled," Air India said.

The airline said it is providing hotel accommodation and also offering full refunds on cancellations or complimentary rescheduling if opted by the passengers.

Air India also said it is making alternative arrangements to fly passengers to their destination at the earliest.

The airline, which on Monday resumed flights from Ahmedabad to London Gatwick with a new code AI159 instead of AI171 of the flight that crashed on June 12, had to cancel the flight on Tuesday due to unavailability of aircraft.

It denied claims that a technical snag led to the cancellation and maintained that it has made alternative arrangements for the affected passengers to their destination and offered full refunds on cancellations or complimentary rescheduling if opted by them.

Air India's official website confirmed that the AI-159 flight from Ahmedabad to the Gatwick airport in London stands cancelled after being rescheduled. The plane was scheduled to depart at 3 pm from the Sardar Vallabhbhai Patel International Airport (SVPIA).

"Flight AI-159 from Ahmedabad to Gatwick (London) has been cancelled today (Tuesday) due to the unavailability of the aircraft, resulting from airspace restrictions and additional precautionary checks, leading to longer than usual turnaround of aircraft, and not due to any technical snag as claimed," an AI spokesperson said.

"We regret the inconvenience caused to our passengers and have made alternative arrangements to fly them to their destination. We are providing hotel accommodation and also offering full refunds on cancellations or complimentary rescheduling if opted by passengers," he added.

Consequently, flight AI-170 from London (Gatwick) to Amritsar on June 17 stands cancelled, the airline said.

Iran has closed its airspace due to its ongoing war with Israel, affecting flights headed to Europe.

AI's direct flight from Ahmedabad to London was earlier known by its assigned code 'AI-171'.

Airport sources said the flight having code AI-171 was suspended after the horrific crash which claimed 270 lives, including 29 people on the ground.

It resumed operation on Monday (June 16), five days after the crash, with a new flight code AI-159, said an airport official.

Separately, an Air India flight from San Francisco to Mumbai via Kolkata suffered a technical snag early Tuesday, requiring passengers to deboard during a scheduled halt at the Netaji Subhash Chandra Bose International Airport.

The termination led to chaotic scenes at the Netaji Subhash Chandra Bose International Airport as the 211 passengers on the Boeing 777-200 LR tried to convince officials to let them reach their destination at the earliest.

The Tata Group-owned carrier did not issue an official statement.

Sources said Air India is making "special arrangements" to fly the stranded passengers to Mumbai. No further details were available.

Usually, the carrier flies directly to Mumbai from San Francisco but the ongoing geopolitical events, including the closure of Pakistani airspace, have led AI to reroute it and take a "technical halt" in Kolkata.

Flight AI-180 landed in Kolkata at the scheduled time of 12.45 am, even though it took off one hour late from San Francisco.

According to sources, a technical issue was detected during routine post-landing checks, and the airline decided to do a comprehensive check.

It was scheduled to depart for Mumbai at 2 am, but passengers came to know of the problems only after 2.40 am when the crew announced there was a problem with the left engine, according to a PTI reporter who was on the flight.

However, this announcement was accompanied by a specific promise, that the snag will take up to 25 minutes to get sorted, the reporter said.

However, as the clock ticked by, distraught passengers having connecting flights from Mumbai started enquiring about the progress of the work with the cabin crew, but there was no clear response, the reporter said.

With the Ahmedabad accident being fresh, some passengers also said a delay is better than a mishap, while some wondered how an aircraft which had travelled thousands of kilometres could face problems in the last leg from Kolkata to Mumbai.

The next announcement came at 4.20 am when the pilots sought another 15-20 minutes for rectification of the problem.

The engineers could be seen working on the left engine even as a drizzle continued, but the problem persisted. Finally, around 5.20 am, the pilots announced that a resolution was not possible and asked all passengers to deplane.

After disembarking and passing the mandatory immigration, collecting baggage and passing the customs channels, the passengers were asked to sit in a designated area.

A few passengers pleaded with officials asking for the earliest option to travel to Mumbai. Some got lucky, while others continued to wait.

Finally, an Air India official announced that Mumbai-bound flights were mostly full and convinced a bulk of the passengers to check into a hotel. PTI IAS AA ANZ BAL BAL