Indian airlines have warned crew members to be on their guard, citing an alleged incident on board a recent international flight where there was a suspicious attempt to gain access to the cockpit.

According to an email sent to Jet Airways pilots on Friday, which HT has seen, a passenger allegedly feigned illness and five others claiming to be doctors volunteered medical assistance. After examining the “sick” passenger, they insisted strongly on meeting the captain, but were refused permission.

“Their persistence was suspect and the captain refused to meet the doctors either inside or outside the cockpit,” reads the note.

According to aviation sources, this occurred on a recent Air India flight to London.

A check was subsequently carried out, which revealed the five were Pakistani nationals. “They were all Pakistan passport holders and their contact numbers, when tried, were found to be fictitious. The patient is also being considered a suspect,” the note says.

Similar accounts have been sent to cabin crew at other airlines, with strict instructions that no “unauthorised” person is to be allowed entry to the cockpit at any cost, aviation sources said.

Top intelligence officials, however, dismissed the claims. Air India declined to comment while attempts to elicit a response from the Bureau of Civil Aviation Security also went unanswered.

Other senior government officials who would ordinarily have been briefed on such a matter told HT they were unaware of any such incident. But the aviation sector seemed spooked.

“It has sent shockwaves through the aviation security establishment. All crew have now been intimated to be very alert and strictly adhere to a no-admission into the flight deck policy,” said one pilot with a private airline.