AIR ASIA PLANE : POSSIBLE VICTIM OF WEATHER

December 31, 2014 1:40 PM | Skymet Weather Team

QZ 8501, an airbus 320-200 from Surabaya (Indonesia) to Singapore , crashed in to Java Sea on 28th December 2014 in the morning hours. Aircraft wreckage has been located and few bodies have been recovered, thereby confirming the crash of aeroplane in the Java Sea. Aeroplane was flying on a route in the equatorial region, infested with heavy weather activity because of proximity of Inter Tropical Convergence Zone( ITCZ).

Aeroplane was flying at an altitude of 32,000 feet and had asked for further climb to 38,000 feet along with deviation in route, to avoid weather. The forecast height of the clouds in that area was up to 53,000 feet accompanied with turbulence and wind shear. Northeast Monsoon remains very active during this time of the season in that region and the cloud top can extend up to 60,000 feet along with severe turbulence. Strong winds, hail, icing and severe lightening are the dangerous hazards associated with these clouds. Of course, all these are detrimental to the safe flying operations . Encountering such weather may start indicating inconsistence speed of the aircraft. Any water particles above an altitude of 20,000 feet are in frozen state. Icing and hail, after getting ingested can damage or even result seizure of engines.

On-board equipment, in general and weather radar in particular, is very essential to negotiate any weather activity. The onboard weather radar does paint the cloud picture well but has its own limitations. It can detect the first curtain of wall clouds but fails to provide information about any shadow clouds behind the wall of cloud. Airframe limitation restricts its climb beyond a certain limit and therefore may not be possible to avoid weather by gaining height. In such a contingency, one has to skirt around the vertical clouds. This also is not an easier task, as the manoeuvre needs to be carried out keeping a safe distance from the cloud. Weather situation is very dynamic and developments are rather fast and precarious. It is difficult for the aeroplane to return back for more than one reason. The radius of turn of these flying machines is very large and even the weather activity in the rear section could have possibly worsened and therefore difficult to negotiate. For these reasons, the flying operations are always considered very challenging and complex.

Pilot reaction and his flying skills are very important in such situations. These do vary largely from one to the other individual. Though expected to be so but may not always be commensurate with the experience of the crew. While competency of the crew remains unquestioned but panic situations can cause inappropriate action which ultimately proves disastrous.

Search and rescue operations are also difficult to carry out in such areas, which are prone to inclement weather conditions and prolonged high impact weather activity. Flying low to undertake such operations is very challenging. Even rough sea conditions deter ocean surface operations and also they get confined mostly during day light duration. Low earth orbit military/ spy satellites may cause even false alarm on few occasions.

In this incident, a lot depend on recovery of cockpit voice recorder(CVR) and flight data recorder(FDR) ,to arrive at possible cause of the accident. Recovery of these devices become more significant, as there was no “ MAYDAY” call made by the crew.

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