KUALA LUMPUR, May 2 — Vietnam air controllers breached protocol by enquiring about the missing Flight MH370 only 17 minutes after the plane vanished from radar on March 8, the Department of Civil Aviation (DCA) said today.

DCA director-general Datuk Azharuddin Abdul Rahman said that at 1.19am on March 8, Kuala Lumpur air traffic control had ordered the Beijing-bound MH370 to change frequency to their Ho Chi Minh counterparts, but Ho Chi Minh only enquired about the jet at 1.38am, when they were not contacted.

“If Ho Chi Minh wasn’t contacted by the aircraft, the protocol is five minutes,” Azharuddin told reporters at the MH370 press conference here today.

The DCA chief noted that once MH370 had passed the Igari navigational waypoint in the South China Sea, the plane was officially the responsibility of the Vietnamese air traffic controllers.

Azharuddin then said it was for the controllers at Ho Chi Minh to say why it took them 12 minutes longer than prescribed by aviation protocol before contacting their Malaysian counterparts for verification.

Putrajaya yesterday issued the preliminary report on Flight MH370 that Prime Minister Datuk Seri Najib Razak pledged last week to release, along with other information regarding the missing flight.

But the release has renewed scrutiny over Malaysia’s response to the flight that disappeared in the early hours of March 8 while on its way to Beijing, China with 239 people on board.

Among others, the disclosed documents revealed that confusion that began shortly after the plane dropped off civilian radar and search efforts that were not initiated until four hours after this happened.

The confusion echoes a fumble when AF447 vanished over the Atlantic five years ago. Controllers at first mistook a virtual flight path for the plane’s actual course, according to an official report, which may have delayed a search operation.

Searchers scouring the vast swathes of the remote Indian Ocean off the coast of Perth in Australia have yet to find any evidence of MH370, and have begun scaling back the search for the plane that has been missing for nearly two months.