The Federal Aviation Administration (FAA) issued two Airworthiness Directives (AD) for the Boeing 737 MAX-8 and 737 MAX-9 this week as a result of in the Lion Air crash on October 29, 2018. The crash, which resulted in the deaths of all 189 people on-board, is still being investigated by both Indonesian and Australian officials. According to Business Insider, The FAA issued the directives a day after Boeing released guidance on a potentially faulty sensor, which could result in the aircraft nosing into a dive.

Officials with the Indonesian National Transportation Safety Committee, who have been investigating the Lion Air crash, concluded that a faulty angle of attack (AOA) sensor was likely the primary cause of the incident. As such, both Boeing and the FAA have issued guidance to flight crews on what to do if the AOA sensor fails in a similar manner on their aircraft.

“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,” wrote the FAA in their AD.

According to the FAA, an Airworthiness Directive is a “legally enforceable regulation issued by the FAA in accordance with 14 CFR part 39 to correct an unsafe condition in a product.” The FAA has stated that compliance with this particular AD is mandatory.

According to Bloomberg, several US airlines including Southwest and American operate the aircraft in question. Air Canada and Norwegian Air Shuttle do as well, and since the plane was introduced Boeing has sold 219 737 MAXs.

As regulators continue to scrutinize the aerospace company, Boeing announced earlier this week that it would be delivering a lower number of 737s than expected; however, the aircraft manufacturer claims that supplier issues are to blame. According to Reuters the company states that it intends to increase production in the final two months of this year to boost production numbers.

“The deliveries for the balance of the year will be backloaded,” said Boeing’s Chief Financial Officer, Greg Smith, during a conference. “You’ll see a lighter October than you would typically, and you’ll see higher-than-production-rate delivery profile for November and December.”

While relatives of the 189 deceased continue to grieve, Lion Air recently had another mishap with one of its aircraft in Indonesia. According to NDTV, a Lion Air flight leaving Sumatra Island smashed into a pole near the terminal, causing damage to the aircraft’s port side wing. Fortunately, none of the passengers or crew were injured in the accident. Lion Air has since stated that the airport personnel were responsible for the incident, and stated that the aircraft control personnel at the airport sent a letter of apology to the airline.