Close call for SAA vaccine flight after checklist ignored
Had headlined SA Airways (SAA) vaccine flight SA 4272 crashed early on 25 February, it could have decimated the gated golf course community of Serengeti, just south of OR Tambo International Airport.
A little further down the road, Irene, and the leafy suburbs of eastern Pretoria, could have been burning, but the official version of what happened that night is still elusive as both SAA and the Civil Aviation Authority maintain they stuck to air safety protocols.
“There was never any chance that the aircraft could have crashed,” says an SAA pilot, who wishes to remain anonymous.
“The systems on the Airbus A340-600 would never have allowed it, and that is why the computer system immediately went to maximum thrust as the flight hit a snag on ascent.”
The pilot added the episode would have lasted around 30 seconds, and this was not the first time an in-flight challenge of this nature had occurred on the aircraft type.
“There are glitches in some systems on the aircraft,” he said, “but there are so many backup systems and checks and balances that safety is hardly ever compromised.”
In this instance, the 90-ton take-off weight miscalculation (as reported in some media) was not the result of pilot error. Instead, he noted, the crew did not follow their checklist protocols and this was probably to blame.
“The Airbus A340-600 has a particular, yet unsolved, system fault where 90 tons of weight is deducted from the aircraft’s weight as displayed on the screens.
“This happens after all data is input and then, on startup, suddenly the aircraft’s gross weight is different by quite a large margin.”
Exactly 90 tons, every time. The glitch was taken seriously enough by the manufacturer that checking the gross weight display of an aircraft against other checks and balances was made mandatory before take-off.
The Citizen has established there have been around 10 pilots at SAA alone who have experienced this phenomenon.
“When it happened to me, I had to take pictures of the incorrect indicators, submit reams of paperwork relating to the flight as well as draft a full report on what could have resulted in a similar incident,” said the pilot.
“The rules are that, within 72 hours of any reportable incident, the Civil Aviation Authority has to be notified.”
Three weeks later, only because both the aircraft and engine manufacturers were automatically notified of any incident and they queried it, the events of that evening came to light.
“Of course, SAA also receives an automatic notification but for some reason or another it was unsuccessfully hushed.”
The pilot reckoned the crew might not have been fully aware of what was happening, as it was happening.
“All of a sudden there would just have been alarms and warning lights going off, and likely some frantic conversations in the flight deck.”
If the checklist were not followed, the crew would have had no idea their gross weight was incorrect.
“The flight management system on board uses that data, along with other inputs to calculate when the flaps or slats [leading edge flaps] retract and at what speed. Of course, with the incorrect gross weight uncorrected, every calculation would have been skewed.”
This begged the question about what the CAA’s waivers related to. According to an industry expert, the body would not waive airworthiness or any technical problem, “so it must have something to do with the currency of pilot training or license validity”.
The CAA did not respond to questions about the incident at the time of going to print and neither did SAA, save to note it would wait for the outcome of an internal investigation.
Yet SAA issued notes that the pilots followed all processes and procedures as required.