Expectedly, media coverage of the inquiry into the Mangalore accident addresses the sensational rather than the substantial. As a result, the real contributors to the accident have been pushed backstage while limelight seeks and chases the obvious.
James T Reason had very lucidly expounded on accident causation through a theoretical
‘Swiss Cheese’ model according to which various layers of a hierarchical organisational structure are visualised as linearly aligned slices of cheese. If each layer has holes (failures), negative activities weave through the holes in successive layers to cross the last layer and cause an accident.
Non-availability of a radar at Mangalore airport — which should have positioned the flight in an ideal air position for a safe landing — was the first ‘hole’. However, by itself, non-availability of the radar was not critical; alternative procedures existed, and were followed.
Probably due to this factor, at a certain point of the approach, the flight was higher than what the ideal approach path (indicated by the Instrument Landing System (ILS) indicator in the cockpit) demanded. The excess potential energy of the massive aircraft was not dissipated in time and the crew probably found themselves over the runway threshold with an overshooting, higher-and-faster-than-prescribed approach.
Written incident report
Lo and behold the next layer of structural cheese, is replete with holes. The airline had an operational circular in place which ordained that every missed approach (aborted approach, with the aircraft going around for another attempt to land) be conveyed to the airline management as a written Incident Report.
As the rendering of such a report was followed by an investigation and a possible escalation to the DGCA, the captain would have been inhibited from a decision to go around by the consequence associated with an investigation. So, faced with two choices — a bad approach (possibly followed by a bad landing), or raising an incident report and facing an investigation, the captain chose the former.
With his impressive flying experience he might still have managed a reasonably safe landing albeit it might have been harder than normal. The high speed would have necessitated an early touchdown with a high downward velocity (euphemistically termed by pilots as ‘firm’ landing). However, another ‘hole’ in the organisational cheese lay ahead. The airline had another operational circular (both these circulars have since been withdrawn) that made the reporting of a hard landing mandatory; general opprobrium and an investigation logically followed the submission of such a report.
So again, the captain would have decided to wash off some of his excess speed by floating extra, crucial distance after having rounded off over the runway. Eventually the situation became critical, and all systemic defences broke down leading to the late and wrong decision to go around, and thence the pile up. There were other ‘holes’ too. The Crew Resource Management in the cockpit — a term encompassing, inter alia, the behavioural aspects of captain-copilot interaction under normal and abnormal circumstances — was apparently a weak area.
Apparently, the co-pilot repeatedly advised the captain to go around — an advise that was ignored, possibly due to a high trans-cockpit authority gradient ie the huge difference between the flying experiences of the captain (over 10,000 hours) and the co-pilot (2,000 hours). The circumstance of the captain dozing off to sleep has generally been glossed over by media and aviation discussions as a common practice; the term ‘controlled rest’ has been used to condone the act.
It is apparent that such a practice is commonplace on long flights; it is equally apparent that this is in violation of procedures. There is another ‘hole’ here inasmuch as there exist practices in the field which represent a departure from procedures as defined by the management.
James T Reason’s accident causation model, albeit projecting weaknesses in organisational structures, is not a systemic model but is essentially premised on human errors which take place at various organisational levels, finally leading to an accident to some action against which there are nil or weak defences in the structure.
The ongoing inquiry, being ably conducted by a professional with huge aviation experience, will undoubtedly dwell on these (and other) organisational and structural aspects of this accident’s causation. The quintessential message that will undoubtedly emerge would be that an organisation ought to be constantly reviewing its structures, procedures and practices so as to detect ‘holes’ created by human error.
(Gp Capt Sachdev is a former Air Force officer)
