Foreign object damage and dropped object programs in aviation safety

¶ … Foreign Object Damage (FOD) and the Dropped Object Program (DOP) Affect Aviation Safety

Civil aviation in the United States has achieved a remarkable safety level, recording less than one accident per million departures (Amalberti & Sarter, 2000). This ranks aviation among the safest industries in the world; however, based on the anticipated growth in air travel (the current number of 25 million flights annually worldwide is expected to double by the year 2010), it is not enough to simply maintain the existing standards (Amalberti & Sarter, 2000). The studies of the aviation industry's long-term worldwide growth potential, even allowing for a recognized near-term business downturn, continue to project a doubling of the global passenger system by 2015 (Karber, 2002). In fact, unless the aviation industry is able to reduce is already low accident rate even further, the increased traffic volume will inevitably result in an average of 25 accidents per year, with over 1,000 fatalities. Since 70% to 80% of all aviation accidents are considered to involve some degree of human error, it only makes sense to pursue those programs and initiatives that improve on those factors that contribute to the incidence of aviation accidents in the first place. To this end, this paper provides an overview of how foreign object damage and the dropped object program affect aviation safety and typical instances and causes of such safety hazards. A discussion of potential solutions to the problem and recommendations is followed by a summary of the research in the conclusion.

Review and Discussion

Background and Overview. According to Gregory R. Clark (1990), foreign object damage (FOD) is any damage to an aircraft that is of a noncombat nature. For example, Clark notes that debris on the runway could be sucked into the engine, or kicked-up by the aircraft's wheels causing damage to the fuselage. Likewise, birds sucked into engine intakes were also considered FOD. "In Vietnam there were instances of friendly aircraft being sabotaged by our own troops.Such incidents took place toward the end of the war, and were attributed to the overall decline of morale within some military units in Vietnam. The Air Force and Navy referred to such sabotage as 'fodding'" (Clark, 1990, p. 184). It has been estimated that human error is involved in 70% of aircraft accidents and maintenance error is becoming a significant area of concern to the aviation industry. In fact, of 14 major accidents recently investigated by the National Transportation Safety Board, half involved maintenance deficiencies. (Hobbs & Williamson, 2003).

Reasons for Foreign Object and Dropped Object Damage. In their book, Cognitive Engineering in the Aviation Domain (2000), Amalberti and Sarter note that, aside from gravity, the greatest hazard facing a modern aircraft comes from people, and most particularly from the well-intentioned but frequently unnecessary physical contact that is required by outdated maintenance schedules. "Before this claim is dismissed as mere provocation," they write, "consider the following data from Boeing (1994)" (p. 4). The data the authors cite is shown in Table 1 below, which indicates the top seven cited causes of 276 inflight engine shutdowns:

Table 1. Top Seven Causes of 276 Inflight Engine Shutdowns as Reported by Boeing (1994) [Source: Amalberti & Sarter, 2000].

Incomplete installation 33%

Damaged on installation 14.5%

Improper installation 11%

Equipment not installed or missing 11%

Foreign object damage 6.5%

Improper fault isolation, inspection, test 6%

Equipment not activated or deactivated 4%

Figure 1 below illustrates these figures graphically:

Figure 1. Top Seven Causes of 276 Inflight Engine Shutdowns as Reported by Boeing (1994).

The costs associated with such inflight engine shutdowns can be catastrophic, both in terms of human life and the economic consequences associated with such events. According to Davis (1993), such maintenance and inspection failures ranked second only to controlled flight into terrain in the list of factors contributing to onboard fatalities, causing the deaths of 1,481 people in 47 accidents between 1982 and 1991; however, the costs of maintenance failures are more likely to be counted in terms of money rather than casualties. Obviously, these types of losses can be enormous. For example, one major airline estimated its annual losses due to maintenance lapses at approximately $38 million (Amalberti & Sarter, 2000). Likewise, Graeber (1996) reported that an inflight engine shutdown, for instance, can cost up to $500,000 in lost income and repairs; each flight cancellation can cost up to $50,000 and each hour of delay on the ramp can cost $10,000 (Graeber, 1996).

Typical efforts to understand the causes of aviation maintenance errors generally begin by describing the observable forms that the errors assume; for instance, the British Civil Aviation Authority reported that the most frequent maintenance errors were incorrect installation of components, the fitting of wrong parts, and electrical wiring discrepancies. Other researchers examined in-flight engine shutdowns in which maintenance errors were cited as the primary cause and found that incomplete installation of components was the most common error, followed by parts being damaged during installation (Hobbs & Williamson, 2003).

Potential Solutions. The taxonomies used to assess aviation safety issues have been based on the outward forms of errors (these have been termed error phenotypes) and behavioristic descriptions. Such descriptions, though, tend to be domain specific, and fail to provide any significant insights into error causation or informed guidance for corrective interventions. "Cognitive models of human error, however, may help to reveal fundamental forms, or underlying error genotypes. These models can be applied across domains or tasks and are likely to represent powerful tools to assist in the understanding of errors and the circumstances in which they occur" (Hobbs & Williamson, 2003, p. 187). On such initiative targeted at reducing the incidence of FOD-related errors was launched by the U.S. Safer Skies and the Flight Safety Foundation's and Approach and Landing Accident task force. These groups have made it a priority to reduce the U.S. aviation accident rate by 80% from its 1998 level by 2007 and to influence reduction of the global rate; to this end, checklists, videos and training aids have been being distributed to U.S. airlines as part of this initiative (Thomas, 2001). These types of formal models of accident causation and operational investigation systems, though, are generally based both on the concept that such human errors are not random events but, instead, take place in response to various causal factors that can be identified and controlled. In this regard, an aggressive dropped object program is the foundation to effectively managing the problem (Hobbs & Williamson, 2003).

In order to reduce the potential for errors and their catastrophic consequences in the aviation industry, there clearly must be solutions that fit the need; however, such solutions need not be overly sophisticated or complex in order to be effective. For example, in their book, Organizing Genius: The Secrets of Creative Collaboration (1997), Warren Bennis and Patricia Ward Biederman, the "Skunk Works" was the name given to Lockheed's top-secret facility where an elite corps of aeronautical engineers and fabricators built radically new aircraft. Because of the sensitivity involved in such projects, the Skunk Works had always encouraged a collaborative approach to their fabrication processes, and the authors point out that the Stealth Bomber project was one such endeavor. "The Skunk Works had always developed its new planes in a highly collaborative manner, taking good ideas from anyone involved in the process, from engineers to test pilots. A new, all-but-invisible stealth fighter was no exception" (Bennis & Biederman, 1997, p. 4). No matter how careful the fabricators and engineers tried to be, though, there were continued incidents involved foreign object damage to the aircraft and its components.