Ice and the weather were 'certainly a factor' in the private jet crash in Florida on Sunday afternoon, according to federal officials.
uncertain
Ice → accord → officials
Nine people were killed after the Learjet 60 nosedived into a multi-lane highway outside Palm Beach, exploding into an enormous fireball.
asserted
Learjet → kill → fireball
In roughly one minute, the $2million business jet travelling from Austin, Texas, to the Bahamas plunged over 25,000ft into the ground, crashing into a residential area of the county and killing everyone on board.
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jet → travel → board
'We have light, clear ice that is manageable and moderate turbulence,' 20-year-old co-pilot, Nathalia Filgueiras, told the Miami Air Route Traffic Control Centre at 12.47pm.
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pilot → have → 12.47pm
Cruising at 35,000 feet and requesting a climb to 37,000 feet, the two-engine Bombardier-made jet then flew into a thunderstorm cell at around 12.48pm.
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jet → cruise → 12.48pm
The aircraft suddenly entered a catastrophic dive exceeding 20,000 feet per minute, prompting the crew to declare an emergency.
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aircraft → enter → emergency
The final devastating transmission came at 12.49.17pm: 'We’re out of time.'
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We → come → time
Flight-tracking data from ADS-B Exchange showed that the jet had plunged around 27,000 feet in approximately one minute before its signal was lost.
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signal → track → minute
The Learjet 60 nose-dived into an intersection in disturbing dash cam footage before bursting into flames
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Learjet → dive → flames
The pilot of a doomed Learjet aircraft that crashed into a fireball in Palm Beach, Florida may have flown directly into the eye of a thunderstorm before the tragedy, a meteorologist says
Nathalia Gadelha Filgueiras, 20, was co-piloting the Learjet 60 and could be heard in distressing audio warning air traffic control that the aircraft was coming down
As moist storm air rises and cools, ice crystals form.
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crystals → doom → control
'Anytime you get moisture up in that cold air, you can get icing conditions,' Robert E. Joslin, a professor of practice in the department of aerospace engineering at Embry-Riddle Aeronautical University, told the New York Times.
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Joslin → get → Times
According to the National Transportation Safety Board (NTSB), flying in icing conditions can present 'operational risks'.
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flying → accord → risks
Ice impacts the airframe and engines, which can make it more difficult to maintain the plane’s path and speed and to remain level.
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it → impact → path
As little as a quarter-inch of ice on the edge of a wing can 'cause sudden departure from controlled flight,' and ice accumulation on some equipment 'can cause flight instruments to cease operating and can affect airspeed, altimeter, and vertical speed indicator indications,' the NTSB said.
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NTSB → 'cause → airspeed
'It sounds like the plane iced when they flew through the cell,' Daniel Bubb, a former pilot who now teaches at the University of Nevada, Las Vegas, told the Times.
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who → sound → Times
'They thought at first it was light to moderate icing.
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it → think → ?
But then it sounds like it got really severe.
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it → sound → ?
'
'The plane can become almost uncontrollable,' he added.
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he → become → ?
He said he believed that the jet might have stalled.
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jet → say → ?
'They couldn’t recover from it, and they crashed,' he concluded.
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he → recover → it
According to Dr. Joslin, as the Learjet started to lose altitude, its aerodynamic burden would have become untenable.
uncertain
burden → accord → altitude
'When those airloads get excessive, it can also lead to structural failure, which can exacerbate the situation,' he said.
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he → get → situation
Ice accumulation on the cockpit windscreens can also restrict the pilots' vision of the plane, which is critical as a backup for avoiding terrain collision, aircraft collision and adverse weather, he added.
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he → restrict → collision
As Filgueiras and her co-pilot were attempting to steer their way out of a fatal scenario, they could have been flying blind.
But even if ice was a factor, human error may have also played a part.
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error → attempt → part
A Learjet 60 has three mechanisms for de-icing: electric heaters in the forward edge of the wings and horizontal stabilisers; an inflatable rubber bladder that can expand to break up ice; and the ability to circulate warm exhaust over the wings.
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that → have → wings
But for any of the de-icing options to work, 'the pilots have to activate them,' Mike McCormick, the former director of air traffic control at the Federal Aviation Administration and a professor at Embry-Riddle, told the newspaper.
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McCormick → work → newspaper
'So that’s going to be the big question,' he added.
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he → go → ?
'Were the pilots aware of and were they informed that they were entering into weather conditions that would contribute to ice accumulations?'
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that → inform → accumulations
Gregory A. Feith, a former senior NTSB investigator, theorised that the jet probably encountered 'clear ice', suspended water droplets that cover much more area than other kinds of ice encountered in flight.
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that → theorise → flight
The pilots may have underestimated the damaging impact the ice had on the flight controls, he added.
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he → underestimate → controls
They then attempted to deal with the turbulence by climbing, which may have induced a 'violent pitchover,' he said, triggering what's known as a 'tailplane stall'.
uncertain
what → attempt → stall
Investigators have not yet disclosed whether any structural failure took place, but some people on social media noticed that the jet's horizontal stabilisers appeared to be missing in photographs from right before the plane hit the ground.
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plane → disclose → ground
'We do have some indication that the aircraft was breaking up before impact,' Tom Chapman, a National Transportation Safety Board member, said at a news conference on Monday.
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Chapman → have → Monday
His remark suggests turbulence may have played a role in the crash.
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turbulence → suggest → crash
As the jet approached the storm cell, Filgueiras described 'moderate turbulence,' with the Learjet experiencing changes in altitude of 600 to 700 feet, as per her remarks to the flight control centre in Miami.
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Learjet → approach → Miami
'That’s a lot of displacement for a turbulence encounter,' said Patrick Smith, a pilot runs the aviation blog Ask the Pilot.
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pilot → ’ → Pilot
He posited that the horizontal stabilisers could have been 'torn away by unusually strong turbulence or improper reaction to unusually strong turbulences,' but caveated it was too early to tell.
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it → posit → turbulences
Dr. Bubb said there was one clear lesson amid the tragedy.
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Bubb → say → tragedy
'This, to me, is just a textbook example of exactly what we’re taught when we’re pilots, and that is, don’t fly through thunderstorms, because you just don’t know their severity,' he said.
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he → teach → severity
Adam Robinson, 45, and his wife Helen Sharp, 40, were onboard the Learjet 60 alongside their toddlers Emma, four, and Charlie, two, when it crashed
Jeffrey Gregory, 55, of Gilbertsville, Pennsylvania, was piloting a Learjet 60 when it nosedived into a road near West Palm Beach, Florida on Sunday afternoon.
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it → crash → afternoon
…and 41 more, not listed.
The Aporia
