[Article originally published on electroverse.net on Oct 15, 2020]
Four hours into a September 2017 Air France flight from Paris to Los Angeles one of the aircraft’s four engines spontaneously exploded.
“Is there a problem?” read an incoming message from air traffic controllers to the pilots — a question initially met by confusion; that is, until a photo (taken on a passenger’s phone–shown below) was hurried to the cockpit by a flight attendant:
There was indeed a problem — the front portion of an engine had fallen.
The plane, an Airbus A380, made an emergency landing in Canada two hours later. Thankfully no one was injured. However, regulators warned that the incident could have played out differently had debris from the explosion hit the aircraft instead of plummeting more than 11 kilometers to the frozen Greenland ice sheet below..
The ordeal set French authorities on a mission to find the lost engine pieces and pinpoint the root cause of the problem.
This required investigators to survey miles and miles of inhospitable Greenland ice sheet, a task made perilous by crevasses, brutal snowstorms, limited daylight hours, and the constant threat of polar bear attacks.
Within just days of the incident, helicopters were dispatched and investigators were scouring the pure white landscape for signs of the engine. After one week and three unsuccessful search flights the terrain was already buried under thick layers of freshly fallen snow, and with months of harsh winter weather ahead investigators decided to resume the search the following spring.
Spring 2018 soon rolled around and an additional team of investigators had joined the effort on foot, wielding ‘ground penetrating radar’–a device that looks like a lawnmower and is commonly used by archaeologists searching for buried artifacts.
Unfortunately though, their extensive efforts over the spring and summer failed–in part because the radars weren’t searching deep enough below the icy surface; the ice had grown too thick and was masking the debris–and with another brutal winter fast-looming the search was once again put on pause.
That winter it was discovered that one of the investigators had previously developed a four-wheeled robot called ‘FrostyBoy’ (shown below) used to map crevasses. The robot, designed by a Mr Lines, was recruited by the BEA to assist the recovery effort — and indeed, FrostyBoy proved to be a game-changer.
On a routine search for cracks, the rover’s sensors picked up an abnormal reading. The robot had–by pure happenstance–rolled over the engine fan’s exact resting place.
“We’re ridiculously lucky that it happened the way it happened,” Mr Lines said of FrostyBoy’s chance detection. It gave his robot, a project he worked on while pursing his PhD at Dartmouth, a small but bizarre claim to fame. However, the job was far from done.
In June 2019, Mr Lines and a team of Icelandic mountain guides flew by helicopter to the excavation site in SW Greenland where it was quickly discovered that retrieving the front section of the engine presented its own set of problems.
In fewer than two years the fan hub fragment had been buried by a staggering 12 feet (almost 4 meters) of compacted snow.
During the 2017-18 and 2018-19 seasons the Greenland Ice Sheet gained a combined 686 billion tonnes of snow and ice (DMI), totals that added to the astonishing 544 billion tonnes gains in 2016-17–the fifth highest in record books dating back to 1981.
Note, these totals don’t account for the annual losses due to the breaking off–or “calving”–of icebergs from the ice sheet’s edge. However, it must be stressed that calving events usually occur when an ice sheet is EXPANDING, not shrinking; furthermore, icebergs breaking off a glacier aren’t necessarily “lost” to the ocean, they can continue existing like some island extension of the sheet.
The dig team put-up a small dome-shaped tent to shelter from the severe winds during their three-day-long excavation effort. And at night they slept with rifles next to their sleeping bags as a precaution in case of polar bear attacks.
It turns out that the population of these majestic, potentially deadly Arctic bears is actually on the rise.
“The number of polar bears has quintupled in the past 50 years from about 5,000 to about 25,000 today,” writes Dr. Jay Lehr; with zoologist Dr. Susan Crockford going further, writing in 2019 that approximately 39,000 polar bears exist in the wild, with that number–against AGW Party prophesies–increasing.
The first few meters of snow and ice above the engine fan shoveled out easily, said Mr Lines; however, the team needed a chain saw to hack apart the thick, compacted layers of frost further down. The crew also carved a ramp into the excavation site so that a sleigh operated by a pulley system could be used to shuttle the 20 metric tons of snow out of the pit.
“We had a lot of sunshine because the sun doesn’t really set [at that time of year],” Mr Lines said; “So we just worked through the night, and then went to bed for a few hours and then woke up and just started digging again.”
Finally, on day three, the tips of the engine’s fan blades came into view.
An industrial heater was used to melt ice away from the fan before the makeshift pulley system hauled it out to surface level.
In footage of the excavation (shown below) the crew are seen to whoop and applaud as a helicopter airlifts the giant fan fragment–still largely intact–out of the pit.
The battered piece of debris later proved vital in understanding what actually went wrong on the 2017 Air France flight.
Investigators determined that it wasn’t a maintenance issue, as previously thought, rather the problem was a phenomenon called “cold dwell fatigue” which caused the metal used in the engine’s fan to fail far sooner than anticipated–a metal which is widely used across the aerospace industry, highlighting an area for improvement which could prevent future, potentially deadly incidents.
Also rather helpfully, the dig also revealed that ice and snow are building at tremendous levels on the Greenland Ice Sheet. Recent years, as discussed above, look to have reversed the naturally occurring trend of loss — a reality visualized below: