Passengers have criticised the airline over its poor communication following the incident.
Video / Alyse Wright
The Latam flight altitude loss incident on a Boeing 787-9 Dreamliner was most likely a “once-in-a-lifetime” freak event, an aviation commentator says.
And a pilot who flew Boeing and Airbus planes said the plunge on flight LA800 from Sydney to Auckland was something very few pilots would everexperience.
“These are called black swan events,” pilot and aviation teacher Ashok Poduval said.
He said speculation was unhelpful but broadly speaking, a sudden loss of altitude could happen if an autopilot system malfunctioned or a plane experienced clear air turbulence.
The latter mostly occurred at the edge of jet streams in high latitudes such as sub-polar areas in the Northern Hemisphere - not the Tasman Sea.
Pilots were trained to deal with severe turbulence.
“At the time I don’t think any pilot has time to be scared.”
Basic training kicked in and a pilot worked to regain control, Poduval said.
“Turbulence is something which almost all professional pilots will do their best to avoid,” Poduval added.
He said in most cases, radar could anticipate turbulence with high accuracy.
But if it was unavoidable, passengers would be told to attach seatbelts and crew would work to secure any fittings and loose objects.
“There’s this thing called latching the trolleys. Those are the things that cause injuries.”
Chile’s Directorate General of Civil Aviation said New Zealand’s Transport Accident Investigation Commission would investigate, and Chile would send a representative to join the inquiry.
Poduval said manufacturer Boeing would also investigate.
“I would be surprised if they aren’t on the way already,” he said of Boeing.
Latam is the only airline flying directly between NZ and South America. Photo / Brett Phibbs
The digital flight data recorder would be examined, Poduval added.
“It records all the parameters in flight.
“Then there is the cockpit voice recorder. They will definitely pull that and analyse the information on there.”
He said it was standard procedure for pilots to be interviewed for the investigation.
Aerodynamic engineer Simon Hradecky, who runs the Aviation Herald website in Europe, said speculation about flight LA800 was rampant - and unhelpful - but the most plausible scenario seemed to be a loss of control over instruments.
“From what I understand, what they told the passengers after landing, possibly in a private talk, it looks like the instruments went blank.”
Hradecky said the plane might not have responded to any flight control inputs for a matter of seconds.
He said even if that scenario was true, it was still unusual and the 787-9 had very few problems in its history.
Some of the Dreamliners did experience lithium battery fires in 2013, prompting an investigation which ended in 2014.
But the Federal Aviation Administration (FAA) in 2016 adopted an airworthiness directive for all Boeing 787–8 and 787–9 planes relating to cycling of either the plane electrical power or power to the three flight control modules (FCMs).
That directive followed a report indicating that all three FCMs might “simultaneously reset” if left powered on for 22 days.
“The computers that control the flight command surfaces might reset at the very same time if the airplane is powered up for 22 days,” Hradecky said.
“I would assume that maintenance will reset the computers every time the airplane goes through a check.”
It seemed outlandish to imagine those checks were not carried out for 22 days, he said.
Hradecky said the LA800 plunge was most likely a “once-in-a-lifetime accident”.
But if the incident was indicative of broader possible problems, the FAA would probably issue an urgent emergency airworthiness directive.
“The 787 doesn’t have any real issues after the initial battery problems were sorted out.”
That incident on a flight from Singapore caused multiple serious injuries.
Pilot Kevin Sullivan years later told the West Australian he lost control of the plane when the autopilot disconnected as the aircraft was cruising at 37,000 feet.
North Shore grandfather Fuzzy Maiava and Auckland woman Jenaya McKay were flight attendants when QF72 nosedived twice.
The first plunge was 650ft and in the second it plummeted 400ft.
Maiava was flung into the ceiling and suffered injuries that left him unable to work and in chronic pain.
John Weekes is the online business editor. He has covered court, crime, politics, breaking news and consumer affairs.
