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| Photo: planespotters.net |
What Happened?
FAA received several reports from some operators of the two Boeing type, that the "Auto-Throttle" (it's a system that allows a pilot to control the power setting of an aircraft's engines by specifying a desired flight characteristic, rather than manually controlling the fuel flow.), remained engaged in the IDLE mode when the flight crew advanced the thrust levers to conduct a balked landing (a go around initiated after touchdown, but before the thrust lever selection). Once airborne, the thrust levers moved back to IDLE. This caused a reduction in airspeed and eventually stick shaker activation.
The 787 Flight Management Block software currently installed introduced an auto-throttle software anomaly, which disables one element of the automatic throttle disconnect logic.
The 777 Airplane Information Management System (AIMS) software introduced similar auto-throttle anomaly, which would behave in the same way as previously described in 787.
How Boeing Acted?
The Boeing Company issued Boeing Flight Crew Operations Manual Bulletins on March 25th and March 24th for 787 and 777 airplanes respectively. These operational manuals include all the necessary information about this anomaly and provide instructions to flight crews for conducting balk landing and go-around. Boeing and its suppliers are now working on an operational software to solve this issue of auto-throttle anomaly.
Boeing Software Issues
In the passed couple of years, Boeing has experienced many software issues on several types. One of those issues was a deadly one! The MCAS (Maneuvering Characteristics Augmentation System),which was installed on 737MAX, was a clear example of a fatal software issue.
We also remember the directive issued by FAA about model 787 ILS landing in some airports, also due to a software anomaly.
