Sunday, February 26, 2012

Airblue, Airbus A321-231, AP-BJB: Accident occurred July 28, 2010 in Margalla Hills , Pakistan

By Captain S. Afaq Rizvi

The inquiry report into the Airblue crash released to the media on Dec 20, 2011) holds the pilot solely responsible for the tragedy. Controlled Flight into Terrain (CFIT), they call it. Why is it that the verdict in air accident investigations is nearly always “pilot’s error”? The answer of course is simple: “Because the pilot is dead!”

At Islamabad on the day of the crash, all the systems were serviceable, the Enhanced Ground Proximity Warning System (EGPWS) worked perfectly, the Air Traffic Controllers were meticulous, but the captain? “He showed anxiety, confusion and geographical disorientation; his air crew failed to display superior judgment and professional skills; flying discipline was breached and procedures violated. The captain’s behaviour towards the first officer was harsh, snobbish and contrary to established norms. He humiliated, demoralised and bullied the first officer creating a communication barrier; the undesired activities of the captain curbed the initiative of the first officer and created a tense and undesirable environment, etc. etc.”

This elaborate charge sheet against the captain of the ill-fated flight does seem a little harsh. Especially when he is not there to defend himself. From what I know of Captain Pervaiz Iqbal Chowdhry he must have changed tremendously to fit this picture.

Whenever an accident takes place a “who done it?” type of investigation begins. There is a search for the black box. We start looking for gun-powder marks and bullet holes. The captain’s diet and demeanour are scrutinised. And the usual scapegoat emerges. Insurance companies then take over and compensation battles begin.

The real purpose of an investigation, that is to prevent such a tragedy from happening again, is lost completely. A little objectivity perhaps could help.

The runway at Islamabad is used from both ends: Northwest (30) and Southeast (12). Most of the time runway “30” is used and is the only one equipped with an ILS (Instrument Landing System). Runway “12” has been begging for an ILS for years. If it had one, the Air Blue ‘crash’ perhaps would not have happened. To get to the pulse of this accident you have to put yourself in a pilot’s shoes.

Occasionally, when the wind direction demands landing on the south-eastern runway, pilots still follow the dated system of approaching towards the northwest and when the runway is sighted they circle around to position themselves visually for a landing from the completely opposite direction. The ground radar also manoeuvres the aircraft in a more or less similar pattern in the ‘down wind’ vicinity of Runway “12” (Fig. 1). In rain and poor visibility; and the proximity of the Margalla Hills, this can become critical for a large airliner.

In the good old days, small twin-engine propeller aircraft circled quite comfortably in the vicinity of the Margalla Hills. But today, giant jet airliners whose radius of turn covers many miles are required to make the same old circling approaches. This can be compared to a little Suzuki which makes a U-turn on a wide road quite effortlessly whereas a large oil tanker literally hugs the opposite edge of the road to make space for the same turn (Fig. ‘1’).

A uniform, homogenous cloud ceiling is never there. Clouds don’t follow rules. Pilots have to fly low under this ceiling to avoid getting back into the clouds. The Ground Proximity Warning Systems and the radar know nothing about the thin layers of Stratus clouds that lurk around. There are occasions when a gap in the clouds has to be negotiated. Options get limited. Many a pilot has missed a heartbeat when blinded for a fraction of a second by a wisp of a cloud, flying low under an overcast sky.

Different shades of light between dusk and dawn give very deceptive versions of the landscape. Flying in and out of rain the vision gets blurred. The runway has to be kept in sight from one side of the aeroplane and on the other side are the hills. Whilst still in a bank the captain of a giant airliner makes space for a U-turn at more than 200 mph. He can easily overdo it. But must we test his skills in this precarious environment? Isn’t avoiding the hills a better option?

Internationally when a circling approach is necessary, visual guidance on the ground is provided. The south-eastern runway at the old Hong Kong airport is provided with an Instrument Guidance System (IGS). A circling approach is then carried out from over a conspicuous checker-board pattern painted on the ground, leading to a crescent of high intensity lights to the final approach away from high hills.

In New York, the final approach from Canarsie to Runway “13 L” provides guiding lights in a curve on the ground to keep the aircraft away from densely populated areas. “Lead-In” lights may be too expensive or even unnecessary at Islamabad. An ILS or any non-precision Instrument Approach System would do.

The existing VOR/DME facility can be relocated, if at all necessary. A descent from overhead the VOR outbound towards the northwest to a designated approach altitude; a procedure turn towards the southwest; followed by a measured descent on the inbound radial towards Runway “12”, is all that is required (Fig. 2). Even an NDB approach on the same pattern would suffice.

Any Instrument Approach towards Runway “12” would make it unnecessary for the aircraft to fly in the vicinity of the Margalla Hills (Fig. 2). An ILS approach at both ends of the runway would, of course, give it an ‘International’ look, besides making it safer.

The principal is simple. Don’t make large airliners fly low in the vicinity of the Margalla Hills in poor weather conditions and they won’t crash into them. It wouldn’t even matter if the captain was really the ‘monster’ described in the investigation report.

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