Jet engines not supposed to fail
Nothing like a loud bang at 35,000 feet (FL350) westbound over the North Atlantic in late November 2018 to make the sleepiest economy passenger wake up quickly.
Subsequent bangs from the American Airlines (AAL) Boeing 777200’s right engine quickly had the cabin crew’s attention and even though the explosions were somewhat muffled forward of the cockpit door, Captain Robert Matthews (63) also heard them, saw the EPR fall as EGT rose and knew there would be paperwork. Spoiler alert: This Triple-Seven didn’t make it to Miami from Paris as filed but didn’t make the evening news either. Consider how routine it was for thousands of airplanes to cross the U-boat-infested North Atlantic every day during World War ll without incidents more serious than running out of wine. In the piston-engine days of DC7s and Constellations, the flight engineer, an airborne mechanic, routinely nursed a misbehaving radial, whilst giving Ernie Gann new material for his next novel. Jet engines provide far less drama, Captain Sullenberger’s bird-sucking experience notwithstanding. In Captain Matthew’s three-decade AAL career, he had never shut a turbine down in flight and six miles above the ocean isn’t the ideal location to learn how to handle losing one, especially when you only have two engines.
Whilst ETOPS sounds like a supporting monster in Homer’s Odyssey, it really means Extended-Range Twin-Engine Operations. Or: Two engines will safely haul hundreds of passengers across the ocean, because jets are so reliable and two are cheaper to run than four. Until one engine fails and then the other engine, the one still turning, is expected to take you back to land, although at a lower altitude and slower speed, giving the crew more time to run through pages of emergency checklists, notify ATC and try not to consider how big and cold the ocean is below.
Flying across the Atlantic is common enough, but not simple. Domestically, instrument pilots are used to receiving radar service from departure to arrival. However, it is hard to construct radar sites on water, so trans-Atlantic crews will hear, ‘Radar service terminated,’ as coastal lights fade behind the tail. Non-radar lateral and longitudinal (same altitude) separation standards are huge. Put simply, traffic operating above 28,000 to 43,000 feet enters the North Atlantic Tracks (NAT), which are parallel airways 60 miles apart, arcing between North America and Europe.
Generally, westbound traffic takes the northern tracks and east bounders use the southern routes. Track positions change based on the jetstream and turbulence. Without radar, aircraft fly in-trail 10 minutes apart. Pilots make position reports and arrival estimates for the next two fixes. Controllers receive these reports digitally or via scratchy HF and adjust flows accordingly. It’s 1940s’ ATC procedures augmented with datalink and satnav. Vertical separation is a skinny 1000 feet, so to avoid wake turbulence from a heavy above, lower traffic is permitted to offset one mile from the centre of the track.
On 29 November 2018, when American Flight 63 was 650 miles west-northwest of Shannon, Ireland, its right Rolls Royce Trent 892 experienced a compressor stall, a disruption of smooth flow of air through the engine. Not good, but the flight crew, as Captain Matthews said, ‘Reacted within seconds.’ The causal factors will only be determined months hence, but immediately the crew had to shut down, get down, turn around and declare ‘Mayday’, before letting the cabin crew and passengers know what was happening without panicking anyone at 35,000 feet above the North Atlantic. Here is how Matthews put it: “In an emergency, we get task saturated very quickly, even in a minor emergency. The captain has a lot to think about, just the nature of what comes with command. You worry first about safety and resolving the emergency, but also legalities, procedures and policies. Not least of these are keeping the flight attendants in the loop and briefing the passengers.”
Training is everything. Pilots rehearse this unlikely scenario in recurrent simulator sessions, so when the ‘s--- hit the fan blades’, the crew reacted as trained with the FO reading checklists whilst the captain flew the airplane. The Engine Limit, Surge, Stall checklist automatically popped onto the electronic checklist display. Combined with memory items, they secured the failed engine, but left it at idle so the engine generators could continue running as well as engine and pneumatic-driven hydraulic pumps, bleed air and pressurisation. All within accepted procedure. However, after an hour, the engine over heated and it was shut down, although the APU had been fired up to provide electrical power.
Aviate, navigate, communicate. They flew the airplane and after initial power loss, turned (as procedure demanded) 45 degrees from the track and descended, because one engine wasn’t going to keep them at FL350. Their choices came down to diverting to Keflavik, Iceland, where weather was awful or back to Shannon, Ireland, where it was better. Turning, they contacted Shandwick, the oceanic controller, announcing (not requesting) that they were heading back. Shandwick knew what to do and all doors opened for the single-engine Triple Seven now descending to FL210.
Matthews flew the ILS on autopilot’ but turned it off at 400 feet AGL to land the half-million-pound B777 by hand, even though it was perfectly capable of autoland. Brakes smoked a bit after stopping on the 10,000-foot runway, but fire crews declared them safe to taxi and Matthews did so to the gate. When things went bang at 35,000 feet, Captain Matthews was three weeks from retirement. He had made over 900 trans-Atlantic crossings in his 20 years of international flying, which, besides Europe, included South America, polar flights to Asia and even Moscow. This flight was supposed to have been his penultimate crossing before hanging up his gloves, but when asked what he wanted after landing at Shannon, Matthews replied, “to retire.”
This wasn’t to be. American Airlines offered to let Captain Matthews fly his final trip from Ireland to Miami. He accepted and the next day, with fire trucks arcing water cannon streams over the replacement Triple Seven, Captain Matthews pulled up to the gate, as a 40-year aviation career wound down with a healthy turbine whine and not a bang.