Two Takeoff Overruns Highlight Safety Issues On The Ground

Air Safety Week, Jan 31, 2005

Low arousal states go hand in hand with undetected error, poor situational awareness and missed vital actions. Is this type miscue easier to make (and miss) at night? Most assuredly - because there are fewer visual cues and night depth perception is less likely to hint at the building situation until it is upon you.

So all it takes is for the pilot to forget a standard call or the flight engineer to become distracted or incapacitated or incorrectly set a power? Not exactly; you have to consider the additional complications of sudden alarm. Unfortunately, the cockpit voice recorder (CVR), located in the tail, was destroyed - so it's all conjecture as to what extent sudden alarm was vocalized by the pilots or FE (or other cockpit occupant). But the sudden noisy application of max power and the sparkling tail-drag are clear indications of instant dismay. The drag of the tail-skid and the high angle of attack would not have helped acceleration but the wheel marks up to the berm show that the aircraft was quite light on its wheels and may have had some chance of making it over or through the treetops about a 1,000 feet beyond the berm.

If the berm had been built with a gradual ski-jump incline instead of a sudden near vertical slope, it may have helped launch the plane, and the seven member crew may have lived to tell the tale. But the accident chain was completed, as always, by that conventionally classic final link. We are forced to ask why that berm was there - as the fatal denominator and divisor of aircraft structural integrity.

Runway Design Considerations

If designers use a tall frangible stanchion to mount approach lighting or a navaid (such as a localizer antenna), then it needs to be stabilized (so as not to wave around in a strong wind). Perhaps when mounted higher up, on a berm, it is easier to keep clear of snow and foliage growth - or perhaps the radiating characteristics are improved (for cat II ILS). Being so far beyond the end of the physical runway, it will be below the minimum climb gradient and so it will meet minimum ICAO specifications for screen height. But beyond any such consideration, it is undeniably a nasty obstacle for an aircraft overrunning a runway on rejected takeoff or grasping for altitude. It could also be argued that an aircraft landing well short on the reciprocal due to windshear might meet that berm at high-speed. So the circumlocutory argument comes back to (or rather becomes) "need it be there?" We would guess that eventually it won't be there.

The counter-argument states that a takeoff on any number of runways would have left this crew in an equally perilous state - the middle of a metropolis, for example. While conceding that point, the pertinent argument becomes "but why have an obstacle that need NOT be there?" We could dismiss it as being "the luck of the draw" but that is unnecessarily fatalistic.

Separate Incident Highlights Overrun Hazards

The crew of Emirates Flight 764, an A340-313, was more fortunate. The aircraft barely made it airborne off the 14,500-foot-long Runway 21R's overrun at Johannesburg's Jan Smuts Airport, South Africa, on April 9, 2004. The aircraft was bound for Dubai with 216 passengers and 14 crew but did not get airborne until it had passed well beyond the end of the runway, loudly blowing three main gear tires and damaging the brakes and flaps (which locked up). On any other Johannesburg runway, they'd never have gotten airborne because there would have been no usable overrun beyond the departure threshold. However, a late hasty application of take-off/go-around (TOGA) power (at that point of noise-induced dismay) got them safely airborne, albeit more than 150 meters into the grassy overrun. Initially this accident was put down to MFF (mixed fleet flying of A330, A340-300 and A340-500s), with their different load parameters (AUW's 233 to 375 tons), aircon packs on (A330) or packs off (A340) and disparate engines (thrust ratings and numbers of).