Firm News

Boeing Issues Memo on 737 Jets After Turkish Airlines Flight 1951 Crash

Posted on Mar 11, 2009

Boeing officials issued a memo asking pilots who fly Boeing 737 jets to pay careful attention to their flight instruments after Dutch investigators concluded that a faulty altimeter caused the crash of Turkish Airlines Flight 1951.

The Turkish Airlines1951 from Istanbul to Amsterdam dropped from the sky on approach to the landing strip broke into three pieces near Schiphol Airport in the Netherlands on February 25, 2009. Eighty people were injured in the crash.

The Boeing 737 is the most widely flown jet in commercial aviation. More than 6000 are currently a part of commercial fleets around the world.

According to CNN.com, Jim Proulx a company spokesman said, "Boeing reminds all operators to make sure flight crews pay close attention to all primary flight controls during critical stages of a flight."

The memo states that there was a malfunction of one of the planes altimeters. An altimeter measures altitude above the ground. One of the two altimeters was giving erroneous information, which indicated that the aircraft was 7 or 8 feet form the ground when it was actually about 2,000 feet in the air. The plane was on automatic pilot and the erroneous reading caused the automatic throttles to decrease the planes air speed.

The memo recommends that operators inform their flight crews of the details of the investigation and remind them to carefully monitor their primary flight instruments.

This is not the first incident of this problem with the Boeing 737. Two other flights of 737 aircraft had experienced the same faulty readings, but the pilot in those landings were able to successfully make the landings. The head Dutch investigator said that the automatiac pilot should not be used if there is a threat of the altimeter malfunctioning. In the Amsterdam crash the pilots did not recognize the malfunction until they were too low to recover.

CNN.com further reported that, the Boeing memo notes that "the autothrottle, which uses the left radio altimeter data, transitioned to landing flare mode and retarded the throttles to the idle stop. The throttles remained at the idle stop for approximately 100 seconds during which time the airspeed decreased to approximately 40 knots below the selected approach speed."