The Hudson River touchdown of US Airways flight 1549 has been called a miracle by some folks. How these folks would describe the ingestion of a flock of birds in terms of miraculous phenomena has not been disclosed. Whatever it was, the aircrew certainly performed admirably.

If you look at a map of the flight path and note the timing, one minute after the birdstrike the A320 had descended from 4000′ to 2000′. At this phase of flight 1549, the airplane is heavy with fuel, baggage, and people. They are configured for climbout and are navigating in congested airspace at low altitude.  At least one of the pilots has his head on a swivel watching for traffic while the other is monitoring flight control systems.

After the birdstrike, there would be some seconds of confusion where the pilot and first officer would have to analyze the warning annunciators as well as what story the flight instruments are telling them. Loss of power on climbout means a prompt loss of airspeed. Here the pilot and first officer would coordinate their cockpit duties. One pilot will concentrate on flying the airplane while the other would, for instance, focus on an engine restart, declaring an emergency with the tower or TRACON, notify the cabin crew for emergency procedures, etc.

While the pilots are determining what kinds of flight controls they have to work with and what other failures may be unfolding, they have to establish a standard airspeed that will minimize their decent rate. This gives them more time in the air and correspondingly, more landing options.

An airplane does a coordinated turn by banking the wing and tilting the lift vector in the direction of the turn. As you tilt the wing, the force vector acting against gravity becomes smaller and without coordinated input from other controls and a bit of power, the airplane will begin to sink.

The point is that when you bank an aircraft during a deadstick glide, you will increase the sink rate. Looking at the map, the pilot could not afford to lose anymore altitude by attempting to make a gliding turn to Teterboro to get lined up with the runways. They had no choice but to continue straight forward along the direction of the river and hope they could land in the water without dipping a wing and cartwheeling the airplane.

I’d say the aircrew made a series of good decisions.

Advertisements