Birds Challenge The Air Force
Modern fighter planes are designed to avoid potential threats, such as air-to-air and surface-to-air missiles. Fortunately, the Israeli Air Force (IAF) rarely faces these dangers. In fact, over the years, the IAF may have lost more planes to a neutral party than any enemy. The culprit. Would you believe migratory birds?
Approximately one billion birds traverse the area between the Mediterranean coast and the Jordan mountains, making southern Israel the site of one of the greatest concentrations of migrating birds in the world. This small airspace is also the principal training area of the IAF.
A study sponsored by the IAF recorded more than 117 “bird strikes” annually over a period of more than two decades. Almost half of these affected fighter planes and consequently caused significant financial losses. From 1972-1983, five fighters were destroyed by birds. In 1974, for example, a pilot was killed when a pelican collided with his Skyhawk and penetrated the canopy.
Initially, the IAF attitude was that such “accidents” could not be avoided, but Yossi Leshem, Director of the Society for the Protection of Nature in Israel (SPNI) convinced military officials that studying bird migration patterns might allow them to reduce the number of bird strikes. The problem led to an unusual and mutually beneficial collaboration between the military and Israeli environmentalists to determine the specific migration routes of raptors, the altitude of migration, the time of arrival of migrating raptors, the peaks for each species and how the whole system is affected by changes in climate.
After a five-year study, Israeli researchers from SPNI, the Ministry of Science and Technology and Tel Aviv University were able to map the migratory routes of soaring birds and collect data on dozens of species. The IAF subsequently adopted the B.P.Z. (bird plagued zone) policy and stopped flying within the migratory paths, the altitudes, times of day and season defined in the study. Collisions between migrating birds and fighter planes subsequently decreased 88 percent. No planes have been lost in the last ten years, resulting in a savings of $300 million to the military and the survival of large numbers of birds.
Though the concentration of migrating birds in Israel is extraordinary, the phenomenon of bird strikes is not unique to the country. According to Leshem, over the past four decades, 130 fighter aircraft from 10 Western air forces have crashed, and 40 pilots have died, due to bird strikes. Civilian aircraft have also had collisions.
The United States Air Force (USAF) is well aware of the problem. In fact, it created the Bird Aircraft Strike Hazard (BASH) Team to seek solutions. According to an article in Flying Safety by Maj. Dave Arrington of the Air Force Safety Agency, more than 3,000 bird strikes are reported annually with damage averaging over $50 million. Since 1987, he says, the USAF has lost 14 aircraft and 11 crewmembers have been killed.
The approach BASH has taken is different from that of Israel. For example, in the U.S., 70 percent of the bird strikes occur around an airfield, so BASH tries to control the birds through habitat manipulation and “frightening” to reduce flocking and the number of large birds. BASH is also involved in tracking migration patterns and has developed a Bird Avoidance Model (BAM) that more closely resembles the IAF’s approach. But much of the effort to avoid birds is more subjective, depending, for example, on tower personnel to give aircrews a kind of bird weather report—“Light” if bird activity is at normal low intensity, “Moderate” if birds are in the immediate vicinity and “Severe” in cases of “extreme bird activity.” BASH also works with manufacturers to design planes that will be as bird strike-proof as possible.
The major difference in approach appears to be Israel’s greater effort to harmonize the nation’s security needs with its environment. The result has been to allow the birds to continue their natural migrations while the IAF modifies its behavior. The Americans seem to place a greater emphasis on modifying the birds’ behavior, and using technology to overcome nature. At the risk of being labeled an econut, I’d say Israel has the better approach and the lessons learned by the IAF could be used to improve the safety of civil and military flight and the tracking of birds on a global basis.