A 'Serious' Situation: Malaysia Airlines Pilots Leave Covers on Speed Probes During Takeoff

Pilots on a Malaysia Airlines flight from Brisbane, Australia (BNE) to Kuala Lumpur, Malaysia (KUL), didn't know how fast the aircraft was traveling during takeoff because neither they nor the ground crew removed the covers from the aircraft's external speed probes before leaving the gate.

According to the Australian Transportation Safety Bureau, the pilots forgot to remove the covers — which are designed to keep insects away from the flight tools — before the Airbus A330-300 took off from BNE on July 18. As a result, the cockpit crew had no accurate data on how fast the aircraft was going at takeoff, nor once the plane was in the air.

The probes, which are known as pitot tubes, sit on the outside of the plane toward the front of the aircraft, and collect data on the aircraft's speed. The three covers were still on the speed instruments when the widebody A330 pushed back from its gate and began taxiing down the runway, ATSB Chief Commissioner Greg Hood told news.com.au, resulting in a "serious" situation.

“This limited the amount of information — critical information — that was available to the flight crew during take off,” he said.

The aircraft reached 10,000 feet and then turned back around for BNE, landing safely with no injuries. The investigation notes that the three covers "were partially burned by the heated pitot probes. They each had a hole burned through where the cover folded around the probe in the airstream."

A lack of airspeed data doesn't necessarily in and of itself cause a disaster, but it can lead to one if the situation isn't handled properly. In 2009, Air France flight 447 — also an Airbus A330 — from Rio de Janeiro (GIG) to Paris (CDG) crashed into the Atlantic after a loss of the plane's speed data due to icing over of the pitot tubes. Incorrect actions by the pilots following this loss of speed data resulted in the aircraft nose-diving into the ocean, killing all 228 people on board.

The ATSB is still investigating the Malaysia Airlines incident, which Hood described as serious. Investigators are focusing on the cockpit warnings the flight crew may have received, as well as the procedures of both the flight and ground crew during pre-flight checks of the aircraft. The aviation body has also issued a safety warning to all airlines (PDF file) to review their procedures with the covers to ensure the covers aren't left on the instruments.