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A few days after the Qantas Boeing 747 in flight depressurization, another incident retained my attention, because it’s really a typical illustration how hard decision making can be. An AirMauritius Airbus 330 was hit by a bird while it was rolling for take-off.

The crew decided to abort the take-off, and applied full brakes to get the airplane to a stop. This resulted in brakes over-heating, and one of the tires caught fire. The fire brigade intervened quickly, but the plane was evacuated using the emergency slides.

Can you imagine how quick that situation evolved ? The guys were having a normal take-off, approaching V1 (the speed above which take-off is no longer an option), when the plane hits a bird ! They aborted the take-off, and then got a break overheat alarm, probably followed by a fire alarm. The time between the start of take-off and the end of the evacuation was probably less than four minutes.

So close to take-off, there are only seconds to make a decision, and this is exactly why V1 is for. Should anything occur at a speed bleow V1, the crew aborts the take-off. This is easy when the event is a technical alarm, but if the problem is a sound or a strange vibration, things are much complex. It’s not obvious that both pilot will hear / feel / smell it, and they have to find a common understanding, which can take long seconds, possibly leading to a speed above V1, and to a take-off with a serious doubt…

The rule when flying single engine aircraft is much easier: any problem on the ground stays on the ground. But when the runway is short, and the speed is already high, a non-engine problem sometimes has to come in the air. To make good decisions in such critical moments, a detailled knowledge of the aircraft and its systems is of paramount importance.

The AirMauritius crew certainly knew about the inherent risks associated to an high-speed take-off abortion. Given the huge amount of energy to be dissipated by the braking system, its temperature rises super quickly. Even after low-speed aborted take-off, and visual inspection by the fire brigade is part of the standard procedures.

The picture below ( (c) Tom Philip, via airliners.net) shows how big an A330 landing gear is. The braking system is located within the white discs seen within the main gear assembly. The people standing by the landing gear give a good reference how large the tires are…

You can now better imagine the heat required to start a fire in such a tire, but also the risk that a burning tire represent to the aircraft it belongs to. In the AirMauritius case it is clear that the fire was caused by the aborted take-off.

Was the decision to abort a good one ? It’s hard to comment about it, mostly because no anoucement was made regarding where the bird did hit the plane. Windshield or engine are certainly the most critical parts, but bird strike on the wings or control surfaces can also have serious impacts.

Even if the plane had to get evacuated, it did not suffered major damages, and all passengers are well. On that basis, one can say that the crew made a good job. Could the abortion have been managed another way, or the fire brigade intervention have been more efficient ? One is always smarter after an incident…

I’m looking forward to the conclusion of the investigation, and to the possible recommendations that will be issued. As always, anything that will be said before will be pure speculation, and shall be disregarded.

Links:

More on evacuation procedures

More about airport faune control

AeroNews Network about the AirMauritius incident

Public information from AirMauritius about the incident

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Category: Air Accidents, On Airports and Airlines
Tags: aborted take-off AirMauritius bird strike brakes decision making fire incident tires

A Qantas Boeing 747 flying the London - Hong-Kong - Melbourne route had to make an emergency landing in Manilla. The NTSB initial press release mentions: “The airplane, Qantas flight 30, a B747-400, en route to Melbourne, Australia from Hong Kong, landed safely in Manila at 11:15 am local time. There were no reported injuries among the 346 passengers and 19 crewmembers. The aircraft has a 5 foot hole in the cargo area forward of the right wing leading edge and there is also some wing damage.“.

The oxygen masks were released in the cabin, and the flight descended from Flight Level 290 (29′000 feet) to 10′000 feet and landed safely in Manilla. A video from the cabin is available on Reuters BBC websites (see link below), showing passengers wearing the masks, and the some pictures of the flight information screen displaying an altitude of 10′000 feet.

Some media reports talk about how the aircraft “plunged”. From a passenger point of view, and emergency descent is certainly impressive, but it does not means that the aircraft is out of control or will crash. The purpose of such expeditious descents is to descend to altitudes which provide enough oxygen to allow people to breath normally.

Click here to read more about the mysteries of pressurization.

Aircraft and procedures are designed to cope with such situations, and crews are trained accordingly. Nevertheless, kudos the the Qantas crew who handled it perfectly: the plane landed safely, no one got hurt, and there are no panic signs on the videos.

Regarding the causes, as always, one have to wait the conclusions of the investigation. The NTSB, FAA and Boeing sent experts to support the investigators.

External links:

BBC video, incuding passenger interview and in-cabin images

Reuters video, including in-cabin images

Coverage of that event by CNN, with video

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Category: Air Accidents
Tags: Boeing 747 depressurization Hong-Kong incident Manilla Melbourne Qantas QF30

Do you know about side-step approaches ? The concept is easy to understand: it starts with a standard approach to a given runway, at least until breaking below the clouds base. Then comes the funny part: a short segment to be flow visually, to line-up with and land on a different runway. No guidance, no auto-pilot, just manual, visual flying, at low altitude, and land.

Such procedures exist at several airports with parallel or nearly parallel runways. Apart from being fun and entertaining for pilots, they allow for a better traffic flow management. Typically, if a landing aircraft is slow to vacate the runway, and the second runway is available, the next aircraft can make the side-step, and avoid a go-around - which is much less fun to fly than a side-step.

Side-step approaches have also be in use at Zurich airport for years. Most landings take place on runway 14, and most departures on 28. The third runway, 16, has a 20 degrees offset with 14, but crosses 28 so both can’t be used simultaneously. However, all planes landing on 14 have to cross 28 during taxi.

To make things easier, ATC offered ILS 14 approach with side-step landing to 16, as long as there is no take-off on 28, thus simplifying the taxi procedures. I experienced it a couple of, time as passenger, and I have to say that it’s pretty impressive, particularly for those seated on the right side of the plane (the side-step is a right turn).

This procedure is not longer used in Zurich, after a couple of incidents where bad coordination resulted in loss separation minima. No collision, but planes taking-off flying low over the landing ones. Not good. Click here to read the investigation report about one of these incidents.

I selected three videos from YouTube to show you how funny these approaches are to fly. I did not found any filmed in Zurich. The first one is at Denver, at dusk, in a rather slow plane, flying a side-step to the right.

That one is slightly more… aggressive.

This one in Vienna is even more impressive, as it includes a very long low-level segment over the approach runway, and then a left turn to the landing runway.

Is not that cool ?

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Category: On Airports and Airlines
Tags: approach incident landing side-step swingover Video