Analysis of Helicopter Maintenance Risk from Accident Data

Rao, Arjun H.; Fala, Nicoletta; Marais, Karen

doi:10.2514/6.2016-2135

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…More detail on the helicopter safety literature can be found in the companion article [1]. Our present work is in the spirit of those by Haaland et al [11], Rashid et al [16], and Rao et al [17]. It builds and extends on these works, and it examines some additional dimensions to the problem, including the temporal signature and incubation period from maintenance errors to maintenance-related accidents.…”

Section: Brief Literature Reviewmentioning

confidence: 99%

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

et al. 2019

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In this work, we establish that maintenance and inspection are a risk factor in helicopter accidents. Between 2005 and 2015, flawed maintenance and inspection were causal factors in 14% to 21% of helicopter accidents in the U.S. civil fleet. For these maintenance-related accidents, we examined the incubation time from when the maintenance error was committed to the time when it resulted in an accident. We found a significant clustering of maintenance accidents within a short number of flight-hours after maintenance was performed. Of these accidents, 31% of these accidents occurred within the first 10 flight-hours. This is reminiscent of infant mortality in reliability engineering, and we characterized it as maintenance error infant mortality. The last quartile of maintenance-related accidents occurred after 60 flight-hours following maintenance and inspection. We then examined the “physics of failures” underlying maintenance-related accidents and analyzed the prevalence of different types of maintenance errors in helicopter accidents. We found, for instance, that the improper or incomplete (re)assembly or installation of a part category accounted for the majority of maintenance errors with 57% of such cases, and within this category, the incorrect torquing of the B-nut and incomplete assembly of critical linkages were the most prevalent maintenance errors. We also found that within the failure to perform a required preventive maintenance and inspection task category, the majority of the maintenance programs were not executed in compliance with federal regulations, nor with the manufacturer maintenance plan. Maintenance-related accidents are particularly hurtful for the rotorcraft community, and they can be eliminated. This is a reachable objective when technical competence meets organizational proficiency and the collective will of all the stakeholders in this community. We conclude with a set of recommendations based on our findings, which borrow from the ideas underlying the defense-in-depth safety principle to address this disquieting problem.

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Section: Brief Literature Reviewmentioning

confidence: 99%

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

et al. 2019

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“…In previous research, we showed that maintenance-related errors or violation accounted for approximately 10% of accidents in 1982-2008. 12 In our current dataset, faulty maintenance (e.g., missed detection or incorrect installation) was almost equally likely to result in fatal (32.1%) and non-fatal (30.3%) component failure accidents. Not surprisingly, critical flight systems including the rotor system and the rotor drive systems were most affected by negligent maintenance.…”

Section: Airframe/component/system Failure/malfunctionmentioning

confidence: 98%

“…Details about the post-2008 accident coding system can be found in Ref. 12. The NTSB records different fields related to aircraft type, geographic location of accidents, phases of flight, severity of injuries and damage, crew details, and type of maintenance carried out ( Figure 1).…”

Section: Features Of the Ntsb Accident Databasementioning

confidence: 99%

Comparing Hazardous States and Trigger Events in Fatal and Non-Fatal Helicopter Accidents

Rao

Marais

2016

16th AIAA Aviation Technology, Integration, and Operations Conference

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Helicopter safety literature generally focuses on identifying the causes and contributing factors for fatal accidents. It identifies the top mechanical and crew-related problems that lead to fatal accidents, and intervention strategies to reduce fatal accidents and improve cash survivability. In this paper, we argue that data from non-fatal accidents is an underused resource that could be used to better understand the reasons for several types of fatal accidents. If fatal and non-fatal accidents share similar stories, we can leverage information in non-fatal accident reports to reduce not just the number of fatal accidents, but rotorcraft accidents overall. We seek to identify and compare the top hazardous states (e.g., loss of control) and trigger events (e.g., incorrect cyclic input) in fatal and non-fatal accidents. We analyzed 5051 helicopter accidents that occurred in 1982-2008. Fatal accidents constitute a small proportion of accidents (15.2%), while the remaining 84.8% were non-fatal. Inflight loss of control (LOC), controlled flight into terrain/object (CFIT), weather, failure to maintain physical clearance/altitude from objects, and system/component failure comprised the top five hazardous states, which accounted for nearly 90% of fatal accidents. Poor inflight planning/decision making by pilots was most likely to trigger both fatal and non-fatal accidents LOC accidents. Decision-making errors also frequently triggered fatal CFIT accidents. The high proportion of non-fatal accidents provides an opportunity for in-depth interviews of pilots to understand the rationale behind the decisions and the actions that followed. Seven out of eight system/component failure trigger events involved the main rotor system and the rotor drive system, highlighting the importance of these systems for rotorcraft operations. Critical flight components such as tail rotor blades and gearbox, and transmission drives were equally likely to fail in both fatal and non-fatal accidents. In some cases the nature of terrain, phase of operation, and on-board protective gear were the difference between life and death. Nomenclature ASIASAviation Safety Information Analysis and Sharing CFIT Controlled Flight into Terrain or Object

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“…Each accident is also coded using a set of codes for occurrences, findings, and phases of flight to facilitate trend analysis (NTSB, 1998). Rao et al (2016) provides a detailed discussion of this system. The NTSB coding system is based on an event-based model, where one event leads to another, but not all aspects of accidents are events.…”

Section: Introductionmentioning

confidence: 99%

Analysis of General Aviation Fixed-Wing Aircraft Accidents Involving Inflight Loss of Control Using a State-Based Approach

2021

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Inflight loss of control (LOC-I) is a significant cause of General Aviation (GA) fixed-wing aircraft accidents. The United States National Transportation Safety Board’s database provides a rich source of accident data, but conventional analyses of the database yield limited insights to LOC-I. We investigate the causes of 5,726 LOC-I fixed‑wing GA aircraft accidents in the United States in 1999–2008 and 2009–2017 using a state-based modeling approach. The multi-year analysis helps discern changes in causation trends over the last two decades. Our analysis highlights LOC-I causes such as pilot actions and mechanical issues that were not discernible in previous research efforts. The logic rules in the state-based approach help infer missing information from the National Transportation Safety Board (NTSB) accident reports. We inferred that 4.84% (1999–2008) and 7.46% (2009–2017) of LOC-I accidents involved a preflight hazardous aircraft condition. We also inferred that 20.11% (1999–2008) and 19.59% (2009–2017) of LOC-I accidents happened because the aircraft hit an object or terrain. By removing redundant coding and identifying when codes are missing, the state-based approach potentially provides a more consistent way of coding accidents compared to the current coding system.

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Analysis of Helicopter Maintenance Risk from Accident Data

Cited by 5 publications

References 10 publications

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

Comparing Hazardous States and Trigger Events in Fatal and Non-Fatal Helicopter Accidents

Analysis of General Aviation Fixed-Wing Aircraft Accidents Involving Inflight Loss of Control Using a State-Based Approach

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