An Aeroflot Airbus diverted to Ekaterinburg late last week after a pitot heating failure. The scheduled service was carrying 155 passengers and crew. The pilots noticed the heating of their static and dynamic ports had failed soon after the plane had begun to deviate from its proper flight level.
Aeroflot Airbus diverts to Ekaterinburg
According to a report in The Aviation Herald, an Aeroflot Airbus A320-200 was en route from Moscow’s Sheremetyevo Airport to Omsk. The aircraft, registered as VP-BNL, was operating flight SU1762.
This flight is a scheduled daily service that typically pushes back late in the evening for the three and a half-hour flight. Omsk is 2,740 kilometers east from Moscow, situated just north of the border with Kazakhstan.
After departing from Sheremetyevo at 22:05 on Thursday, October 8, The Aviation Herald says the aircraft was around 130 miles east of Ekaterinburg and cruising at 35,000 feet when it began to deviate from its proper flight level. The deviations were only small, about 150 feet. Shortly after, the pilots observed the problem with the static and dynamic ports.
The pilots then decided to divert to Ekaterinburg. The aircraft touched down safely at 05:30 local time on Friday, October 9.
After cooling their heels in Ekaterinburg for nine hours, the passengers continued onto Omsk on another aircraft.
The Airbus involved in the incident, VP-BNL, is a leased plane that has been with Aeroflot since May 2013. After landing at Ekaterinburg, it stayed on the ground for several days. But by yesterday, October 11, it was back in Moscow.
An aircraft’s static and dynamic ports, also known by the more generic names of pitot systems, measure airspeed. There are several different sensors on modern aircraft that make up the pitot-static system. In addition to airspeed, they gauge Mach number, altitude, and altitude trend. Errors are considered highly dangerous. Fly too slow, and a plane might stall. Fly to fast, and a plane might encounter all sorts of structural threats.
When issues with pitot systems can go terribly wrong
One of the best-known examples of where wrong airspeed measurements can cause serious problems was the Air France Flight 447 mid-Atlantic crash in 2009. The plane stalled and couldn’t recover, crashing into the ocean. Two hundred and twenty-eight people died.
Investigations later found the autopilot had disengaged, likely due to the iced-over pitot tubes. That caused incorrect airspeed readings. The pilots took over from the autopilot, but they overcompensated, believing the aircraft to flying at a different speed to which it was.
The plane stalled and could not come out of it. There were various issues at play here, including human error, but it highlights how critical correct readings from the static and dynamic ports and why the Aeroflot pilots elected to divert rather than continue to Omsk.
While the Air France example had a catastrophic outcome, various airlines over the years have also had serious issues with pitot systems. In 1974, three crewmembers on a Northwest Airlines Boeing 727-200 died when their plane crashed after a stall and rapid descent caused by the crew’s reaction to erroneous airspeed readings.
Fortunately, on Friday, the plane landed safely, and there were no reported injuries to passengers or crew. While back in Moscow, the aircraft has not yet returned to operating scheduled flights.
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