Table of Contents
Managing more than one task at the same time is daily work in the cockpit operation. In generally, cockpit crew can efficiently deal with the demands of the concurrent tasks, but crew preoccupation with single task to the detriment of other tasks is one of the main causes for operational error in the cockpit. The most typical accident caused by crew preoccupation with one task to the detriment of another tasks is the aircraft crash of a Lockheed L1011 (Eastern Flight 401), the cause of this accident was that flight crew all focused on the landing gear indicator fault to the exclusion of monitoring the aircraft’s gradual descent, which eventually caused the crash. Based on the review of the NTSB (National Transportation Safety Board) reports, Dismukes, Young and Sumwalt (1998) reported that “nearly half of these accidents involved lapses of attention associated with interruption, distraction, or preoccupation with one task to the exclusion of another task “(p.4). Besides, the Australian Transport Safety Bureau reported that there were 325 occurrences involved in pilot distraction on Australian- registered airplane during the period of 1997 to 2004. (Australian Transport Safety Bureau, 2005). The number of accidents and incidents associating with the pilot distarction between 1997 and 2004 are shown in Table 1.
Table 1. the Number of Occurrences Involving Pilot Distraction on Australian- registered airplanes between 1997 and 2004 (Australian Transport Safety Bureau, 2005, p.10)
The data from Table.1 found that there were 325 occurrences involved in pilot distraction on the Australian- registered airplane between 1997 and 2004. The majority of occurrences concerning the pilot distraction were incidents (258), the following occurrences were accidents (65), and 2 serious incidents (Australian Transport Safety Bureau, 2005). The data revealed that the pilot distraction produced great harm to flight safety.
The main factors involed in pilot distraction and interruption
Dismukes, Young and Sumwalt (1998) studied 107 ASRS (Aviation Safety Reporting System) reports in which crews paid not enough attention to one task while attempting to another task. "These reports revealed a wide range of activities that interrupted, distracted or preoccupied the pilots in these incidents" (Dismukes, Loukopoulos & Kimberly, 2001, p.1). The majority of these activities could be placed into one of four categories: (1) communication (conversation among cockpit crew members or with flight attendants), (2) head-down work (reviewing approach chart or programing the FMS - Flight Management System), (3) searching for VMC (visual meteorological conditions) traffic, or (4) abnormal situation or unanticipated situation (Dismukes et al, 1998). The main factors involved in pilot distraction and interruption is shown in Table. 2.
|Factors||% of Events|
|Searching or Responding to Visual Traffic||8%|
Table. 2. Factors Invovled in Pilot's Distraction and Interruption. The most common types of error are related with communication (50%), the following is head-down tasks (16%), abnormal situations (14%), and searching or responding to visual traffic (8%).(Dismukes et al, 2001)
In the 68 of the total 107ASRS incidents the cockpit crew reported that they were interrupted or distracted by some form of communication, the most common type of communication were the conversation or discussion among cockpit crew members, or the conversation between pilot and flight attendant. Although most of the discussion among cockpit crew members is about the flight, the discussion has a potentially negative effect on the pilots because it takes up a large proportion from one’s pilot’s attention to interpret what the another pilot is saying, to work out a proper responses, and to hold those responses in mind until he can give the feedback. Someone might say that it is not hard to stop the conversation whenever other tasks need to be done. However, “the danger is that the crew may become preoccupied with the conversation and may not notice cues that should alert them to perform other tasks” (Dismukes et al, 1998, p.5). Besides, the unessential conversation, especially between a pilot and a flight attendant, should be avoided at a particular time while on aircraft approaching or take off. In the case of the aircraft crash of Delta Flight 1141 at Dallas Fort Worth, a flight attendant had stayed in the flight deck to chat with the pilots for 17 minutes, while the pilots were taxing the airplane and running the checklist. The crash happened because the flight crew never configured the wing’s flaps and slats on the proper position for task off; the NTSB (1989a) reported that "Had the captain exercised his responsibility and asked the flight attendant to leave the cockpit, or, as a minimum, stopped the non–pertinent conversations, the 25–minute taxi time could have been used more constructively and the slat position discrepancy might have been discovered” (as cited in Chute &Wiener, 1996, p.6).
The head down activities such as programming the FMS, reading the approach chart, doing the paperwork, demand substantial amount of pilot’s attention which attending to fulfil these tasks together with other tasks simultaneously; it may significantly increase the possibility of errors occurred in one task or the others (Dismukes.et al, 1998). According to the study of airline accidents from NTSB reports that focus on the crew error during a period of over 12 years, Dismukes (1998) found that “The NTSB concluded that failure to monitor and/or challenge the pilot flying contributing 31 of the 37 accidents” (p.5). Besides, in the 22 of the total 107 incidents Dismukes (et al, 1998) reviewed, the pilot Not Flying reported that they were preoccupied by some kinds of head-down works while they were monitoring the pilot Flying or the aircraft status.
An example of pilot distracted by head-down work:
“….Snowing at YYZ. Taxiing to runway 6R for departure. Instructions were taxi to taxiway B, to taxiway D, to runway 6R….as First Officer I was busy with check-list and new takeoff data. When I looked up, we were not on taxiway D but taxiway W…ATC said stop…." (as cited in Dismuke et al, 1998, p.5).
Responding to abnormal situation
The abnormal situation easily distracts the crew’s attention from other cockpit duties. The abnormal or unanticipated situation requires cockpit crew to put high levels of attention on each of concurrent tasks, such as being aware at the cockpit warning system, detecting and diagnosing the problem, and choosing the correct remedial action; in which the cockpit crew probably cannot pay enough attention to one task while attending to another tasks. Besides, the cockpit crew does not have many opportunities to practice the abnormal procedures, hence in unanticipated situation they have to be required to make more effort and pay greater attention on choosing and implementing checklists than doing the normal checklists; it may distract crew’s attention from other tasks. Furthermore, people often feel great pressures in the abnormal situation; the enormous pressure may cut down pilot’s mental flexibility, and reduce their ability to handle concurrent tasks (Dismuke et al, 1998). Dismuke (1998) pointed out that “abnormal were a factor in 19 of the 107 incidents; Ironically it seemed that one of the biggest hazards of abnormal was becoming distracted from other cockpit duties” (p.7).
Searching for VMC traffic
Searching for traffic may distract pilot’s attention from their preoccupied tasks, such as monitoring the flight status and position. Also, searching for traffic may preempt (interrupt) the pilot’s attention from an intended action (e.g. running a checklist), and then may defer the action, until later time but forgotten by the interruption. Dismuke (et al,1998) found that in 11 of the 107 incidents the pilots reported searching for traffic as a competing activities that distracted or preoccupied the pilots.
The following lines of defends are suggested for preventing or minimizing the cockpit interruptions and distractions
- The communication (conversation or discussion) among cockpit crew members should kept brief, clear (to the point), and concise.
- The Sterile Cockpit rule should be implemented, but the rule should not effect on the communication of emergency or safety-critical information by cabin crew.
- Any conversation or discussion should be interrupted or suspended when the crew is scanning the airplane’s status and position.
- “Define task sharing for FMS programming or reprogramming depending on the level of automation being used and on the flight phase (SOPs)” (Flight Operations Briefing Notes, 2004, p.8).
- Scheduling or re-scheduling head-down work during the time of low workload
- Loud express that “you are going head down” (when the pilot Not Flying is going to the head-down work, the pilot Flying should announce that you are going head down).
Responding to the abnormal or unanticipated situation
- Adjusting the autopilot to keep working in decrease workload, unless there are other required
- The pilot Flying must keep the responsibility of flying aircraft firmly in mind, he /she has to fully concentrate on flying the airplane.
- Complying with the PF/PNF (pilot Flying/ pilot Not Flying) task-sharing under the abnormal or unanticipated situation; the pilot Not Flying should keep great attention on the situation awareness, monitoring, and assist and support the pilot Flying.
- Paying the extra attention to the normal checklists, “because handling an abnormal condition may disrupt the normal flow of SOPs actions; SOPs actions and normal checklists are initiated based on events (triggers); in case of disruption these events may go unnoticed and the absence of the usual trigger may be result in the omission of actions or checklists” (Flight Operations Briefing Notes, 2004, p.8).
Searching for VMC traffic
- “Express a clear and loud ‘I fly, you watch’ call” (Flight Operations Briefing Notes, 2004, p.8).
- As pilots reported searching for traffic as a competing activities that distracted or preoccupied the pilots; so when the interruption occurred, crew need take a ‘three steps process of Identify-Ask-Decide’ to get them back on track, and minimize the possibility of ignoring or forgetting previous tasks: (1) Identify the interruption when it exists (2) Ask, “what was I doing ?or what did I intend to do before the interruption occurred? (3) Decide what I can do to get back on track
(Sources: Flight Operations Briefing Notes, 2004; Dismuke, 2008)
Australian Transport Safety Bureau. (2005). Dangerous distraction: An examination of accidents and incidents involving pilot distraction in Australia between 1997 and 2004. AVIATION RESEARCH INVESTIGATION REPORT B2004/0324. Retrieved from Google: http://www.google.co.nz
Chute, R. D., & Wiener, E. L. (1996). Cockpit/cabin communication II: Shall we tell the pilots? The International Journal of Aviation Psychology, 6(3). 211-231. Retrieved from Google Scholar: http://scholar.google.co.nz/scholar
Didmuke, K., Young, G., Battelle, R. S. (1998). Cockpit interruptions and distractions. ASRS Directline, 10. 4-9. Retrieved from Google Scholar: http://scholar.google.co.nz/scholar
Dismukes, R. K., Loukopoulos, L. D., & Kimberly, K. J. M. A. (2001). The challenges of managing concurrent and deferred tasks. Retrieved from Google Scholar: http://scholar.google.co.nz/scholar
Flight Operations Briefing Notes.(2004). Managing interruptions and distractions. Retrieved from AIRBUS website: http://www.airbus.com/company/aircraft-manufacture/quality-and-safety-first/safety-library