Compressor stall The airliner successfully made a forced landing in a forest clearing without loss of life. On January 15, 2009, US Airways Flight 1549, an Airbus A320, ditched in the Hudson River about five minutes after takeoff. The apparent cause was compressor stall in both CFM International CFM56-5B engines after flying through a flock of birds about 90 seconds after takeoff. This same aircraft may have suffered a compressor stall on the right engine two days earlier. After an incident in which an Airbus A321-200 experienced compressor stalls on both engines during initial climbout on December 15, 2008, an EASA Emergency
Flock (birds) it is specifically the two different behaviours of the species that compose a mixed flock. Within a mixed flock there can be two different behavioural characteristics: sally and gleaner. Sallies are individuals that act as guards of the flock and consume prey in the air during flight. On the other hand, gleaners are those that consume prey living within vegetation. Studies have shown that as resources in the aerial environment increase, the flock will possess more sallies than gleaners. This has been shown to occur during forest fires in which insects have been flushed from vegetation, however this can also