PILOTS TRAINED TO RELY ON INSTRUMENTS
Mr John Tan, lead professional officer of aviation management at the Institution of Engineers Singapore, said the report contains no “conclusive evidence” of a hardware failure.
He said pilots are trained to rely on their instruments, not just visual observation.
“This is probably a situation where they don’t actually have timely information to make a correct decision … they don’t have enough clear warning of what was actually the weather risk ahead,” he said.
“This is different from saying that the pilot made a straightforward error, or one of the hardware components had definitely failed.”
Transport analyst Terence Fan from Singapore Management University agreed, noting that it is difficult for pilots to monitor all conditions across a long flight.
“Because the flight is very long, sometimes you don’t expect the crew to be looking out every minute, because they also have to look at the instrumentation, and they also have to plan the route, so it’s not possible for them to at all times scan everything,” he said.
On the wider implications of weather under-reporting, Mr Tan said a radar that understates risk robs the crew of crucial warning time.
“The fair question is not whether the pilots can predict the exact turbulence, the fair question is whether the system, the entire safety system, has provided enough warning for the pilot to react in a more timely manner.”
He added that while weather radars are generally efficient, they have limits: turbulence, in particular, remains difficult to detect.
“Unfortunately, they won’t actually detect everything out there, particularly in this case of SQ321, it’s actually turbulence, and the technology at this point of time cannot capture turbulence,” he said. “That could potentially be the problem.”
Asst Prof Fan said the airline could not be faulted for missing the earlier radar defects, as their frequency fell below the threshold of three incidents in 10 days and had not resulted in any adverse outcomes.
“So you cannot also fault the airline, because they would have to do this for every flight, for every radar, and that’s a lot of work.”
The investigation findings noted that since the incident, SIA has taken several safety actions, including sending reports of similar radar issues on its Boeing 777 fleet to Boeing and the radar manufacturer.
“Given that this has happened, it certainly makes sense to do a bit more testing,” said Asst Prof Fan.