UPDATE: Thailand grounds Thai Lion Air Boeing 737 MAX fleet

… and US pilots report their problems whilst flying the 737 Max 8 model aircraft.

The Civil Aviation Authority of Thailand says it is suspending the use of the Boeing Co’s 737 MAX 9 due to safety concerns.

The regulator said it will temporarily suspend the use of Thai Lion Air’s Boeing 737 MAX 9s for seven days, starting tomorrow and will continue to investigate safety measures. Thai Lion Air’s three MAX 9 jets will be affected.

The MAX 9s are almost identical to the MAX 8 model Boeing 737 except that it has three additional rows of seats but shares all the same parts, avionics, cockpit and systems.

Its parent company, Lion Air, has confirmed reports it has put on hold the scheduled delivery of four Boeing 737 Max 8 jets while it waits for the outcome of the Indonesian investigation into the October crash off Jakarta that killed 189 people.

Lion Air executive Daniel Putut said the airline needs to know the “root cause” of the accident.

Lion Air ordered 222 Boeing Max planes, including 218 of the Max 8 model and four Max 9 planes. It currently has 10 Max 8 planes in its fleet.

Thailand is the last country in Asia where the jets are registered to issue a suspension, following the fatal crash of a MAX 8 737 in Ethiopia on Sunday.

Thai airlines do not operate the MAX 8 model.

Meanwhile, at least two pilots who flew Boeing 737 Max 8 planes on routes in the US say they raised concerns last November about the noses of their planes suddenly dipping after engaging autopilot, according to a federal government database of incident reports.

The problems the pilots experienced appeared similar to those preceding the October crash of Lion Air Flight 610 in Indonesia, in which 189 people were killed.

In both of the American cases, the pilots safely resumed their climbs after turning off autopilot. One of the pilots said the descent began two to three seconds after turning on the automated system, according to the New York Times.

“I reviewed in my mind our automation setup and flight profile but can’t think of any reason the aircraft would pitch nose down so aggressively,” the pilot wrote.

A pilot on a separate flight reported in November a similar descent and hearing the same warnings in the cockpit, and said neither of the pilots on board was able to find an inappropriate setup.

Another pilot wrote of having been given insufficient training to fly the Max 8, a new, more fuel-efficient version of Boeing’s best-selling 737.

The black boxes, recording the cockpit conversations and all electronic and mechanical systems of the doomed Ethiopian Airlines flight on Sunday, are now being prepared to be sent to either London or the US for urgent examination.