US Federal teams are investigating two high-altitude in-flight bird strikes earlier this week in central Arizona.

The first strike occurred Monday morning and caused skin damage to a Delta Airlines MD90 (N909DA) that had taken off from Phoenix.

Flight 1232, with 65 passengers and five crew onboard, was climbing to a cruise altitude of 30,000ft (9,144m) north of the airport when it struck a flock of birds at approximately 11,000ft above ground level enroute to Salt Lake City.

Upon inspection after diverting back to Phoenix, maintenance personnel found an 18in (46cm) "tear" in the fuselage skin after of the right side flight deck eyebrow window, according to the NTSB. No one was injured in the incident.

The second incident occurred Wednesday morning when an Ameriflight Beechcraft C99 (N330AV) twin-engine commuter hit a bird or flock of birds at roughly the same altitude as it neared Show Low, Arizona, on a flight from Phoenix. The pilot, the only person onboard, received minor facial cuts when the bird hit and broke the aircraft's windscreen. According to Flightglobal's ACAS database, Ameriflight operates 45 C99s and other aircraft types. The FAA is investigating the incident.

According to a government-industry bird strike committee, there were 2,200 bird strikes involving civil aircraft at altitudes of more than 5,000ft above the ground between 1990 and 2008, with the highest altitude incident reported as a collision between an aircraft and a Griffon vulture at 37,000ft off the coast of Africa.

Source: Air Transport Intelligence news