I am saddened by Saturday's crash of the CAL aircraft at the Cheddi Jagan International Airport in Guyana. Along with the multitudes, I applaud the escape of the numerous passengers and crew. That deliverance is easy to deem divine. There is no defining information yet as the black box is going to be analysed and crew interviewed, before an inquiry gives its findings. Right now all we could do is speculate on the cause or causes of the incident. I wish to offer a possibility arising out of my research and experience, and put it in the public domain through your medium.
I start with the assumption that the aircraft was deemed airworthy and the crew as competent as we know them to be at CAL. My input then regards weather conditions that could impact on the craft on approach and at landing. In addition to poor visibility in the horizontal direction due to a variety of meteorological phenomena such as stratus cloud, rain and fog, there are other significant wind factors that could cause a landing hazard and lead to a crash. One assumes also that aircraft instruments were operating accurately and the pilots were given accurate and updated meteorological weather data (atmospheric pressure, QNH, temperature, wind direction and average with gust, actual weather condition in terms of precipitation, intensity, fog and clouds etc) at the terminal.
These reports are done hourly and when conditions deteriorate according to specified international criteria. If there were thunderstorms in the vicinity, not only will lightning be notably important, but vertical and horizontal wind shears could/would be present, and could be unobserved by aircraft instruments and also by ground equipment (Doppler radar), if there were any. These transient wind phenomena are short-lived but temporarily warp the air over the runway and vicinity, also at the landing zone, causing difficulty in aircraft handling; and made worse by the ground surface being suddenly so close.
There is little room for safety manoeuvres since the wind shear could slam the aircraft down harder, cause swerving to one or the other side, and even cause the aircraft to climb again some height. These uncontrollable movements would cause bounce, twists and turns that could lead to breakup of the craft.
I describe a thunderstorm downburst/microburst effect and in the past this has been responsible for major loss of life in very large and well-equipped international airports. Guyana is apparently still in a state of unpreparedness for night landings and is in dubious state to offer/allow and cater for emergency assistance in case of mishap.
Grant Adams
Kansas, USA