In a good news story a USAirways Airbus 320 took off from LaGuardia airport in New York City today, heading to Charlotte, North Carolina. Less than a minute into a routine departure, flight 1549 lost power from both engines, apparently from bird strikes. The pilot glided the aircraft, with 155 souls on board to a water ditching in the Hudson River. A lot of folks got wet and cold, but nobody died.
Any aircraft will glide without power, assuming all the airframe is intact. The problem is the speed it takes to glide, to force air over the wings and generate lift. Commercial aircraft, like the A320 are designed more for flying at cruise altitude and speed, as that is where they spend the majority of their time. Gliders, by contrast are designed to operate at comparatively slow speeds, so the wings are designed to generate lots of lift at low speeds.
Even with gliders, airspeed means lift. No airspeed? It’s called a Stall and the aircraft falls from the sky because Gravity Always Works. A falling aircraft, if pointed nose down, will generate airspeed which means lift again. It is part of any pilot’s rudimentary initial training to stall and recover with power off. In a glider, that’s just another day in the air.
The dangerous part is when you don’t have a lot of space between the aircraft and the planet to dive and gain airspeed, which is exactly what the pilot, C.B. "Sully" Sullenbeger was facing. Initial reports are he was barely at 3,000 feet. If he was at 28,000 feet, he could potentially glide for miles, as there would be a lot of space between the aircraft and the planet: Put the aircraft in a continuous moderate dive, to keep airspeed up, to keep the wings working, would be the principal objective.
Sullenbeger had seconds after losing both engines, to determine where to glide towards. The whole equation of diving enough to keep up airspeed, versus how much space was left between the aircraft and the ground started to come into play. According to reports, the pilot hung a hard left turn and glided it into the Hudson River as slow as possible, without stalling and falling.
Imagine balancing on a unicycle, juggling a Coleman stove, a banana and a live trout, in the back of a pickup truck going down a dirt road, backwards. Now answer your cell phone. That’s what the crew did.
Plus Sullenberger did it in an aircraft not really designed to drive around without engines, which was full of enough gas (weight, in other words) for a flight to Charlotte as well as 154 other souls, freight, luggage, coffee, Coke and carry-ons.
The mere fact that Sullenberger and the rest of the crew got the aircraft down intact is outstanding. That they did it as a water ditching of 81 tons of aircraft doubled the degree of difficulty. At 160 knots/185 miles per hour, water does not give like a grass field under a glider.
That they did it all, without a single loss of life, is a remarkable piece of airmanship. Period. No irony. No smart comments. Just remarkable airmanship.
RoadDave 