WASHINGTON/NEW DELHI/MONTREAL: Amid scrutiny following a fatal Boeing 787 crash in India, U.S. aviation regulators and Boeing have privately affirmed that the fuel cutoff switch design on Boeing aircraft is safe and does not require immediate corrective action.

A Continued Airworthiness Notification issued by the U.S. Federal Aviation Administration (FAA) on July 11 stated it did not consider the fuel control switch design to pose an unsafe condition, even though it was cited in a preliminary Indian investigation into last month's Air India crash that killed 260 people.

The FAA's notice, seen by Reuters, said: "Although the fuel control switch design, including the locking feature, is similar on various Boeing airplane models, the FAA does not consider this issue to be an unsafe condition that would warrant an Airworthiness Directive."

In a separate message to airline operators, Boeing echoed the FAA's stance and said no action is currently being recommended, according to two sources familiar with the matter.

The preliminary report by India's Aircraft Accident Investigation Bureau (AAIB) noted that Air India had not performed a 2018 FAA-recommended inspection of fuel cutoff switch locks, as the advisory was not mandatory.

The report cited cockpit voice data in which one pilot asks the other why the fuel was cut off, and the other replies, "I did not do so." Both switches had flipped from "run" to "cutoff" shortly after takeoff.

Pilot union ALPA India rejected early assumptions of pilot error and demanded to be included as observers in the ongoing probe. "The pilots' body must now be made part of the probe, at least as observers," said ALPA India President Sam Thomas.

Two U.S. safety experts also supported ALPA India's request, though they said the AAIB's report did not appear biased.