A380 jetliner flips business jet upside down in freak mid-air accident

Posted: March 20, 2017 by oldbrew in News, physics, Travel

Image credit: liveandletsfly.com


Wake turbulence rules for A380s require other aircraft to observe minimum separation distances of 5-8 miles in a variety of situations.

A harrowing freak air accident that has only just been revealed saw an Airbus A380 commercial jetliner flown by Emirates cause a much smaller business jet passing beneath it to flip upside down and plummet thousands of feet, reports the IB Times. The incident is a sharp reminder of why passengers should always wear their seat belts.

According to information obtained by the Aviation Herald, on the morning of 7 January an Emirates Airbus A380-800 was flying from Dubai to Sydney. While the aeroplane was en route over the Arabian Sea, roughly about 630 nautical miles southeast of Muscat, a Bombardier Challenger 604 business jet operated by German carrier MHS Aviation passed by 1,000ft beneath it.

A thousand feet might seem like a great distance between two aeroplanes, but the wake turbulence caused by the A380 jetliner was so great that one minute after the airliner passed by above, very high G-force sent the business jet into an uncontrolled roll that turned the aircraft upside down at least three, if not five times.

Both of the plane’s engines flamed out, its Ram Air Turbine would not work and the aircraft plunged 10,000 feet. Fortunately, the aircraft’s pilots managed to regain control over the Challenger 604 using “raw muscle force” and restarted the engines.

The aeroplane was diverted to Muscat airport in Oman for an emergency landing and several of the nine people on board the aircraft were taken to hospital, with one person sustaining serious injuries.

German authorities investigating damage to aircraft

To give you an idea of scale, the Airbus A380 is 73m long and usually weighs between 386-560 tonnes. In comparison, the Bombardier Challenger 604 is just 21m long and weights 17-21 tonnes.

The damage sustained by the Challenger 604 was so extensive that the aircraft has had to be written off. Germany’s Federal Bureau of Aircraft Accident Investigation (BFU) is leading the investigation even though the incident occurred in international waters.

Wake turbulence forms behind an aircraft as it passes through the air. It occurs in the vortex flow behind the aircraft’s wings and is due to lift generated by high pressure below the wing and low pressure above the wing, which creates a sort of horizontal ‘tornado’ behind the wings that sinks downwards in the air until it dissipates.

Usually this phenomena is considered to be most hazardous if it occurs when a jetliner is taking off or landing, which is why such care is taken to allocate slots to aircraft at airports. However, there have been several incidences where wake turbulence has caused incidents in mid-air in the past.

Continued here.

Comments
  1. oldbrew says:

    IB Times also reports a few other A380 incidents e.g. ‘in October 2011, a Qantas Airbus A380 flying from London to Singapore caused a British Airways Airbus A320 to roll over 50 degrees and the autopilot disconnected over Germany. Four people on the British Airways flight had to be treated for minor injuries.’

    Not great if hot drinks are being served :/


    Wake Vortex Turbulence

    ‘ATC traffic separation standards in controlled airspace will not necessarily prevent significant encounters with wake turbulence and the greater risk of injury because both Cabin Crew and some passengers will probably not be secured in their seats.’
    http://www.skybrary.aero/index.php/Wake_Vortex_Turbulence

  2. Damian Scott says:

    “raw muscle force”
    Aren’t these aircraft “fly by wire”?

  3. Dave Ward says:

    Trainee pilots are always warned about the risks of wake turbulence, but it’s not until you’ve actually encountered it for real (I have), that you pay a lot more attention to other aircraft in the vicinity…

  4. Martin Miller says:

    Some time back a private jet carrying all the board of directors for In ‘n Out Burgers encountered the wake turbulence of a 757 while on final approach to John Wayne Airport, KSNA. The crash killed everyone on board. Whenever I landed there (my IFR training ground) we were cautioned with every clearance to land. Fortunately, I never experienced any myself.

  5. Dave Ward says:

    “Aren’t these aircraft “fly by wire”?”

    The A380 is, but not (as far as I can tell) the Challenger. This report:

    https://www.flightglobal.com/news/articles/inquiry-reveals-challenger-604-design-flaw-220738/

    Quotes: “For a high proportion of the remainder of the flight the two pilots had to fly the aircraft manually, which demanded heavy nose-up inputs on the control column to operate the elevators as the sole pitch control”

    Which infers that the control surfaces are still moved by direct mechanical linkages to the cockpit controls.

  6. Annie says:

    I seem to remember a requirement to leave enough room for the 747 years ago when that first came into service. The A380 is larger and surely larger gaps are needed there. It is up to ATC and regulators to stipulate spaces between aircraft and not lay the blame on the A380 per se. It is an excellent aircraft that flies many people per flight safely and quietly.

  7. oldbrew says:

    Annie – see ‘Wake turbulence rules for A380s’ link at top of this post.

    The problem seems to be in mid-air where flight paths are sometimes only separated by 1000 feet altitude, so if that’s what you meant by ‘larger gaps’ then yes, they may need to look again at that.

  8. Bloke down the pub says:

    A couple of years back, a ‘record high’ temp was set at Heathrow airport. The high only lasted for ten minutes or so, and then dropped back. Coincidentally, at that time two 747’s and an A380 landed, being grouped together as they are less prone to suffering the effects of wake disturbance and can thus be landed in quicker succession than could smaller aircraft. Being heavier aircraft, that require a longer landing run, they all left the main runway at the taxiway which runs alongside the weather station. Any suggestion that the high temperature was related to the aircraft, is a scurrilous slur on the Met Office and those who support the theory of CAGW.

  9. Dave Ward says:

    Vortices gradually get larger in diameter, and both gradually drop and drift with the wind, as they extend behind the aircraft producing them. So a vertical separation of 1000ft might be fine if passing directly underneath, or close behind, but not sufficient when several miles behind. As a pilot (particularly in my case of an ultralight aircraft) you have to constantly draw a mental picture of where they are likely to be when sharing airspace with much larger planes. Also when taking off behind other aircraft you have to consider whether your rate of climb (or ANGLE of climb) is going to keep you above the wake vortices from those in front. High angles of attack and the use of flaps also creates larger vortices, so a landing “heavy” is worse than it would be in the cruise.

  10. DavidH says:

    @Dave Ward : Not sure that flaps increase vortices. I recall from my PPL training that wake turbulence was greatest when “heavy, slow and clean” (no flaps for the uninitiated). Flaps reduce the angle of attack at the wing tips. When clean, a greater angle of attack – along the whole wing – is needed and so stronger vortices are generated. Then again, my training was some time ago, so memory may be faulty.

  11. Wayne Job says:

    @davidH It has been a long time ago for me but heavy slow and clean rings a bell. The vortices are broken into small turbulent flows with flaps or speed brakes.

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