The US Federal Aviation Administration (FAA), has told airlines it believes Boeing’s 737 Max 8 model to be airworthy, after two fatal crashes inside six months.
An Ethiopian Airlines plane en route from Addis Ababa to Nairobi crashed six minutes after take-off on Sunday, killing all 157 people on board.
The incident followed Lion Air 737 Max 8 crash in October that killed 189.
Some in the aviation community have called for the aircraft to be grounded pending a full investigation.
But late on Monday, the FAA issued a “continued airworthiness notification” saying the plane was safe to fly.
China, Indonesia, and Ethiopia on Monday ordered their airlines to ground the jet. Aerolineas of Argentina, Mexico’s Aeromexico and Brazil’s Gol have also suspended flights of the aircraft.
The Civil Aviation Authority of Singapore yesterday said it was “temporarily suspending operation of all variants of the Boeing 737 Max aircraft into and out of Singapore”.
The suspension will take effect from 14:00 local time (06:00 GMT).
Other airlines kept flying the 737 Max 8 after Boeing said it was safe.
Shares in Boeing fell by 12.9 per cent on Monday in the wake of the crash.
US Transportation Secretary Elaine Chao said the FAA would “take immediate and appropriate action” if a defect was found in the plane.
FAA chief Dan Elwell said the notification “informs the international community where we are and (gives) … one answer to the whole community”.
Paul Hudson, the president of FlyersRights.org and a member of the FAA Aviation Rulemaking Advisory Committee, called for the plane to be grounded.
“The FAA’s ‘wait and see’ attitude risks lives as well as the safety reputation of the US aviation industry,” Mr. Hudson said in a statement on Monday.
The aircraft came down near the town of Bishoftu, 60km (37 miles) south-east of the capital. The cause of the disaster is not clear, but the pilot had reported difficulties and asked to return to Addis Ababa.
Investigators have found the cockpit voice recorder and digital flight data recorder but it will be a while before the findings are made public.
Visibility was said to be good but air traffic monitor Flightradar24 reported that the plane’s “vertical speed was unstable after take-off”.
The pilot was named as Senior Capt Yared Getachew, who Ethiopian Airlines said had a “commendable performance” over more than 8,000 hours in the air. –BBC