(Corrects story in paragraph 9, 16 to reflect official clarification from ANA that it began inspections last week, not in 2018.)

By Abhijith Ganapavaram and Lisa Barrington

NEW DELHI (Reuters) -India on Monday ordered its airlines to examine fuel switches on several Boeing ( BA ) aircraft models while South Korea ordered a similar measure on Tuesday, as scrutiny intensified of fuel switch locks at the centre of an investigation into a deadly Air India crash. 

The precautionary moves by the two countries and airlines in several others came despite the planemaker and the U.S. Federal Aviation Administration assuring airlines and regulators in recent days that the fuel switch locks on Boeing ( BA ) jets are safe.

A preliminary report into the Air India crash that killed 260 people found the switches had almost simultaneously flipped from run position to cutoff shortly after takeoff. 

One pilot was heard on the cockpit voice recorder asking the other why he had cut off the fuel. "The other pilot responded that he did not do so," the report said.

The report noted a 2018 advisory from the FAA, which recommended, but did not mandate, operators of several Boeing ( BA ) models, including the 787, to inspect the locking feature of fuel cutoff switches to ensure they could not be moved accidentally.

India's Directorate General of Civil Aviation said it had issued an order to investigate locks on several Boeing ( BA ) models, including 787s and 737s, after several Indian and international airlines began making their own inspections of fuel switches. 

The regulator oversees the world's third-largest and fastest-growing aviation market. Boeing ( BA ) planes are used by three of the country's four largest airlines.

PRECAUTIONARY CHECKS

Some airlines around the world told Reuters they had been checking relevant switches since 2018 in accordance with the FAA advisory, including Australia's Qantas Airways.

Others said they had made additional or new checks since the release of the preliminary report into the Air India crash.   

Singapore Airlines said on Tuesday that precautionary checks on the fuel switches of its 787 fleet, including planes used by its low-cost subsidiary Scoot, confirmed all were functioning properly. 

The Lufthansa Group said it had re-checked switches on its 787s since the Air India incident, after initially inspecting them in 2018, and found no issues. 

South Korea's Transport Ministry said it ordered domestic airlines on Tuesday to inspect fuel control switches in accordance with the 2018 FAA advisory. 

"At that time (2018), it was a recommended measure and was not fully inspected," the statement to media said.

Flag carrier Korean Air Lines said on Tuesday it had proactively begun inspecting fuel control switches.

Japan's ANA and Japan Airlines ( JPNRF ) said they were conducting inspections in accordance with the 2018 advisory. 

Taiwan's EVA Air said that it understood that no further inspections of Boeing 787s were required.

U.S. carrier Alaska Air said it has not received guidance from Boeing ( BA ) and is not currently taking action.

Southwest Airlines said it completed inspections of the affected fuel cutoff switches on its fleet in 2018, immediately after the FAA issued its advisory. "We remain engaged with the FAA and Boeing ( BA ) and will take additional action as necessary," a Southwest spokesperson said.

INSPECTIONS

Boeing ( BA ) referred Reuters' questions to the FAA, which did not respond to a request for comment. Boeing ( BA ) shares closed 1.6% higher on Monday after there were no recommended actions in the report aimed at operators of 787 jets or the GE engines.

Over the weekend, Air India Group started checking the locking mechanism on the fuel switches of its 787 and 737 fleets and has discovered no problems, a source familiar with the matter told Reuters on Monday.

About half the group's 787s have been inspected and nearly all its 737s, the source added, speaking on condition of anonymity. Inspections were set to be completed in a day or two.

The Air India crash preliminary report said the airline had not carried out the FAA's suggested inspections, as the FAA's 2018 advisory was not a mandate.

But it also said maintenance records showed that the throttle control module, which includes the fuel switches, was replaced in 2019 and 2023 on the plane involved in the crash.

In an internal memo on Monday, Air India CEO Campbell Wilson said the preliminary report found no mechanical or maintenance faults and that all required maintenance had been carried out.