1 1 Introduction ­CHAPTER MENU 1.1 ­Introduction, 1 1.2 ­Bird Strike: Foreign Object Damage (FOD), 2 1.3 ­A Brief History of Bird Strike, 6 1.4 ­Brief Statistics of Bird Strike, 8 1.5 ­Classification of Birds Based on Size, 10 1.5.1 Small Birds (Less than 2 lb), 10 1.5.2 Small–Medium Birds (2–4 lb), 11 1.5.3 Medium–Large Birds (4–8 lb), 11 1.5.4 Large Birds (8–12 lb), 11 1.5.5 Massive Birds (12–30 lb), 13 1.6 ­Bird Strike Risk, 14 1.6.1 Civilian Aircraft, 14 1.6.2 Military Aircraft, 15 1.6.3 Helicopters, 17 1.7 ­Severity of Bird Strikes, 17 1.8 ­Field Experience of Aircraft Industry and Airlines Regarding Bird Ingestion into Aero Engines, 18 1.8.1 Pratt & Whitney (USA), 18 1.8.2 General Electric Aviation (USA), 18 1.8.3 Southwest Airlines (USA), 19 1.8.4 MTU (Germany), 19 1.8.5 FL Technics (Vilnius, Lithuania), 19 1.9 ­Bird Strike Committees, 19 ­ References, 20 COPYRIGHTED MATERIAL 1.1 ­Introduction Flight has been the dream of mankind as we watch birds soar effortlessly through the sky. Humans have been inspired by the ability of birds to fly and have tried to imitate it. Birds first took to the air about 150 million years ago, while humans first began to share their airspace only in 1903. Unfortunately, when aircraft and birds attempt to use the same airspace at the same time, collisions occur. So, let us first define the term “bird strike”. A bird strike is defined as a collision between a fixed‐ or rotary‐wing aircraft during different flight phases and an airborne Bird Strike in Aviation: Statistics, Analysis and Management, First Edition. Ahmed F. El-Sayed. © 2019 John Wiley & Sons Ltd. Published 2019 by John Wiley & Sons Ltd. c01.indd 1 08-04-2019 18:24:46 2 Bird Strike in Aviation avian creature (usually a bird or a bat) or a group (a flock) of such avian creatures, resulting in the death or injury to the bird, damage to the aircraft, or both. As defined by the Federal Aviation Administration (FAA), near‐collisions with birds reported by pilots also are considered strikes. “Birdstrike” (as one word) and “bird hit” are alternatives for the term “bird strike.” Bird strike with the aircraft’s engine is normally denoted as “bird ingestion.” The hazard associated with bird strike is identified as bird aircraft strike hazard (or BASH). BASH also stands for “birds/wildlife aircraft strike hazard.” Based on the Bird Strike Committee Canada, a bird strike is deemed to have occurred whenever: ●● a pilot reports a bird strike; ●● aircraft maintenance staff identify damage to any module of aircraft caused by a bird strike; ●● ground personnel report seeing an aircraft strike one or more birds; ●● bird remains are found on an airside area or within 200 ft of a runway (unless bird’s death is due to other reasons). A possible collision between an aircraft and a flock of birds is illustrated in Figure 1.1. Ground movements of birds may also pose a threat to aircraft, as illustrated in Figure 1.2. Birds may also collide with missiles during the flight of the missile. Figure 1.3 illus- trates a flock of birds (possibly cormorants) surrounding the Space Shuttle Atlantis in 2002. On 26 July 2005, the Space Shuttle Discovery hit a turkey vulture [1] during liftoff (Figure 1.4). Bird strike leads to the death of bird(s). For the flying vehicle, the aircraft or rocket may experience either a minor or major damage of its airframe and/or engines or may have catastrophic destruction with the loss of some/all passenger lives. Complete destruction of aircraft is mostly caused by significant bird ingestion into engines [2]. 1.2 ­Bird Strike: Foreign Object Damage (FOD) The term “Bird Strike” is usually expanded to include other wildlife species, including terrestrial mammals. Bird strikes cause the greatest amount of FOD (or Foreign Object Damage) of aircraft. (Note that FOD is also the abbreviation for “Foreign Object Figure 1.1 Birds threatening a flying aircraft [27]. Source: An Airbus A330 of China Eastern behind a flock of birds at London Heathrow by NMOS332, B‐6543 is Licensed under CC BY‐SA 2.0. c01.indd 2 08-04-2019 18:24:46 Introduction 3 Figure 1.2 Birds threatening aircraft on ground movements. Source: Courtesy USDA‐APHIS [23]. Figure 1.3 Birds are surrounding Space Shuttle Atlantis in 2002. Source: Courtesy NASA. c01.indd 3 08-04-2019 18:24:47 4 Bird Strike in Aviation Figure 1.4 A turkey vulture flew right into Space Shuttle Discovery. Source: Courtesy NASA. FOD Inanimate Animate Solid Stones Wildlife Humans Grass Rains Ground Food Remains Airborne Wildlife Hail Mechanic Tools Volcanic Mammals Reptiles Birds Bats Insects Ash Figure 1.5 Foreign object damage. Debris.”) FOD (Figure 1.5) covers both animate and inanimate sources. “Animates” include wildlife, grass, and humans. Moreover, wildlife includes ground animates (coy- otes, dogs, deer, and snakes) and airborne animates (birds, bats, and insects) (Figure 1.6). c01.indd 4 08-04-2019 18:24:47 Introduction 5 (a) (b) Figure 1.6 Airborne animates (a) Bird [28]. Source: Bald eagle anatomy by Peter K. Burian, Licensed under CC BY‐SA 4.0. (b) Bat [29]. Source: Flying fox at Royal botanical gardens in Sydney by Hasitha Tudugalle is licensed under CC‐BY 2.0. c01.indd 5 08-04-2019 18:24:48 6 Bird Strike in Aviation “Inanimate” includes solid stones, tools left by mechanics, hail, rain, and food remains. Recently, drones have been added to the list of possible FODs. Drones flying close to airport may threaten aircraft during its takeoff and landing flight phases. On 20 December 2018 flights at Britain’s second busiest airport, London Gatwick, were suspended after several sightings of drones flying near the airfield. Disruption was caused to at least 20 000 passengers in the run up to Christmas. Planes were unable to take off and a number of flights scheduled to land were diverted to other airports. More than 90% of FODs can be attributed to avian creatures [3]. Consequently, a bird strike is one of the most critical FOD. It caused numerous accidents, resulting in aircraft damage and human casualties as well as harmed wildlife. Bats are the only flying mammals. They generally fly only when it is fully dark or at dusk and dawn. Bats are categorized as either “small” or “large” [4]. Small bats are iden- tified as “insectivorous” bats as they feed exclusively on insects, whereas large bats are called “fruit bats” or “flying foxes” (which are vegetarians). Bats of both types are found everywhere in the world, apart from large (fruit) bats which are not found in the Americas. Bat strikes by aircraft are relatively rare and form only a low proportion of all wildlife collisions [5]. Small bats navigate using an “on‐board radar system” analogous to primary radar and thus rarely collide with aircraft. Moreover, fruit bats use only trees and caves as roosts and fly at low level to and from their feeding sites of tree‐borne fruit. Thus, the risk due to strike of a fruit bat with an aircraft is even lower than for insectivorous bats. Humans appear on the list of possible FOD constituents, but it is rare that accidents are encountered. One of the saddest accidents occurred on 17 December 2015, when a maintenance crew member for Air India was sucked into a jet engine of the Airbus A‐319 aircraft at Mumbai airport. The pilot misinterpreted a signal and switched on the plane’s engine, which led to the death of the maintenance crew member. 1.3 ­A Brief History of Bird Strike The first known bird strike occurred in Ohio on 7 September 1905 when Orville Wright struck and killed a bird near Dayton [6]. Orville Wright outlined that this strike occurred when his aircraft hit a bird (probably a red‐winged blackbird) as he flew over a cornfield near Dayton Ohio (Figure 1.7). The human first victim of a bird strike was Calbraith Rodgers. (He had made the first transcontinental airplane flight across the USA, traveling from 19 September 1911 to 5 November 1911.) Regretfully, on 3 April 1912 he flew into a flock of birds during an exhibition flight in Long Beach, California. A gull got caught in an aircraft control cable and the plane crashed into the ocean. The pilot’s neck was broken and he died a few moments later [6] (Figure 1.8). The US Navy’s first fatality due to a bird strike occurred in 1914 [7], coincidentally the same year it obtained its first aircraft. It is fortunate that worldwide no fatalities have ever resulted from bat strike with aircraft. However, bat strike incidents in the USA have steadily increased from four in c01.indd 6 08-04-2019 18:24:48 Introduction 7 Figure 1.7 First bird strike in 1905. Source: Courtesy Orville Wright Museum. 1990 to 255 in 2014, with a total of 1264 cases in total from 1990 to 2014. No complete similar record is available in Europe, while in Ireland five bat strike incidents have been reported over the 10‐year interval, 2006–2015 [5]. In brief, conflicts between birds and aircraft (or bird strike) have increased dramati- cally in the recent years. The main reasons are: ●● A sustained increase in aircraft movements over the last 50 years, with a substantial increase in air traffic worldwide since 1980 [8, 9].