MIAMI – Following the fatal Sriwijaya Air (SJ) flight that crashed on January 9 in the Java Sea, Boeing Issued a Technical Bulletin that advises pilots to monitor aircraft behavior precisely.

According to Bloomberg, Boeing released a safety bulletin advising all pilots to the necessary measures they need to take to ensure control of their aircraft following last month’s fatal crash. Boeing issued the bulletin on February 15, 2021, and sent it to customers all over the world. It aims to “reinforce active flight crew monitoring of airplane state and flight path management to prevent airplane upset.”

The SJ flight No. SJ182 dove unexpectedly shortly after take-off on January 9, killing all 62 aboard. The bulletin does not clearly discuss the SJ fatal crash. However, it is a high-level warning for pilots to watch their aircraft for the kind of difficulties that occurred prior to the accident and how to recover from those situations.

Boeing noted in the bulletin that “Loss of Control In-flight remains the single greatest cause of fatalities in commercial aviation.” As reported by Bloomberg, “this bulletin is meant to reinforce the importance of active monitoring of the airplane state while managing the airplane flight path.”

Sriwijaya Air Boeing 737-524(WL); @CGK2017 – 39283339542. Photo: CC BY-SA 2.0, via Wikimedia Commons

What Happened to SJ182

According to a preliminary report released by the Indonesian National Aviation Safety Committee (NASC) on February 10, less than three minutes after taking off from Jakarta, the left engine of the 737-500 started to lost power while the right engine thrust setting remained the same.

Such uneven thrust settings will cause a plane to bank abruptly if the pilot does not counter the cause correctly. According to the report, there were signs that the pilots were unable to maintain their assigned heading.

Around the same time, the flight crew was struggling to turn during the storm that had ensued, so they may have been overwhelmed. Consequently, 83 seconds after the throttle problem occurred, the plane turned more than 45 degrees to the left. And shortly, it plunged into the Java Sea from a height of almost 3,354m (11,000ft).

Although Indonesian investigators haven’t disclosed the main reason behind the crash, it is clear that the aircraft was out of command in the final 30 seconds of the flight. The Ministry of Transportation of Indonesia reported that it is aware of the bulletin through its direct liaison with the Federal Aviation Administration (FAA) and has taken safety measures based on the NTSC’s preliminary report.

Adita Irawati, spokeswoman for the Ministry said on Thursday that authorities had carried such safety directives before the Boeing safety bulletin.

The Flight SJ182 was plunging into the Java Sea from a height of almost 3,354m (11,000ft). Photo: Sriwijaya Air Flight 182 Speed and Altitude. Phoenix7777, CC BY-SA 4.0, via Wikimedia Commons

Boeing Recommendation

Per the Bloomberg report, Boeing “regularly communicates with customers on how they can safely and confidently operate their airplanes.” The company emphasized that “In close coordination with investigative and regulatory authorities, these latest communications reinforce the importance of industrywide and Boeing guidance and training materials on aircraft upset prevention and recovery.”

Boeing mentions different factors in the bulletin that could induce a loss of control, including instrument malfunctions and pilot improper behavior. Preventing such conflict “involves the active participation of both pilots.” Boeing states.

The manufacturer highlighted that “active monitoring skills are essential to facilitate early detection of conditions that can lead to an airplane upset.” An upset or stall happens when the plane flies too slowly or when the aircraft banks, climbs or descends too steeply.

In addition, Boeing warned about distractions and complacency. On this point, Boeing outlined that “Highly automated and reliable flight control systems have greatly reduced pilot workloads, but the requirement for monitoring complex systems has increased.”

Top: Route of Flight 182 Bottom: Altitude-speed graph of Flight 182. Image: Phoenix7777 – Own work Data source: Route: Sriwijaya Air flight 182 crashes near Jakarta, Flightradar24 KML file Map: Open Street Map

Big Problems Have Small Beginnings

As in the SJ crash, which started with what seems to have been a comparatively minor problem with the jet’s auto thrust system, Boeing argued that pilots shall keep an open eye on signs of irregular flight operation.

Boeing reminds the industry how a simple maneuver can cause this to go awry by stating, “Minor excursions such as simply over banking in a turn or flying slow on approach can progress to a larger divergence from the intended flight path and lead to an airplane upset condition and potential loss of control.”

Featured image: PK-CLC, the aircraft involved in the accident, at Soekarno-Hatta International Airport in 2017, in an earlier livery. – CC BY-SA 2.0, Wiki Commons