The US government has ordered airlines to instruct pilots flying Boeing's 737 MAX on how to handle the potentially deadly flaw that may have caused the Lion Air crash

AP

A Lion Air Boeing 737 MAX 9.

• The US Government has issued an emergency airworthiness directive for airlines operating the Boeing 737 MAX 8 and Boeing 737 MAX 9 airliners. 
• The FAA directive comes one day after Boeing issued a safety bulletin alerting airlines that erroneous readings from one of the plane's sensors can cause the aircraft to enter into a sudden dive.
• The directive orders airlines to update its procedures so pilots are properly instructed on how to react when the faulty sensors cause the plane to dive.
• The Indonesian government believes this condition may have caused Lion Air JT610 to crash in October. 

The US Federal Aviation Administration issued an emergency airworthiness directive on Wednesday for airlines flying the Boeing 737 MAX 8 and 737 MAX 9 airliners. 

The FAA's emergency AD reinforces the safety warning Boeing released on Tuesday.  Boeing's operations manual bulletin that advises airlines on procedures when erroneous readings from one of the plane's sensors lead the aircraft to enter into a sudden dive.

According to the Indonesian National Transportation Safety Committee, these erroneous AOA sensor readings may have triggered an abrupt dive that brought down Lion Air Flight JT610 in October.

"This emergency AD was prompted by analysis performed by the manufacturer showing that if an erroneously high single angle of attack (AOA) sensor input is received by the flight control system, there is a potential for repeated nose-down trim commands of the horizontal stabilizer," The FAA said in the directive.

"This condition, if not addressed, could cause the flight crew to have difficulty controlling the airplane, and lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain."

Read More: The Lion Air Flight 610 crash is the worst airliner accident of 2018

In addition, the agency found that potentially deadly flaw may manifest itself again in other Boeing 737 MAX aircraft.

As a result, the FAA has ordered airlines to revise its flight manuals to provide pilots with specific procedures on how to react when these conditions occur.

Airlines are required to make the changes prescribed by the FAA within three days of the receipt of the directive.

Lion Air Flight 610 crashed in the Java Sea shortly after taking off from Jakarta, Indonesia, on October 28. All 189 people on board the flight were killed. Flight JT610 marked the first fatal crash involving Boeing's next-generation 737 Max aircraft.

The 737 Max, the fastest-selling plane in Boeing history, is the latest version of the company's 737-family of jets. Boeing has more than 4,500 unfilled orders for the 737 Max on its books.

Here's the directive in its entirety:

Get the latest Boeing stock price here.