On the Design of Flight-Deck Procedures - Intelligent Systems ...

Similarly, it has been a common practice (yet not a mandated procedure) in another carrier for the PNF tocall out heights above touch down as the aircraft approaches the runway. The concern was that bymaking these frequent callouts (100, 50, 40, 30, 20, 10, feet above the runway) the PNF must focusentirely on the radio altimeters (heads down), and not on his primary task -- backing up the PF duringthe landing.Guideline #16: Particular attention should be paid in order to safeguard information transferduring critical and high workload phases of flight. Callouts should be economical,unambiguous, and should convey only the information needed by the other crew member(s).They should not distract the crew member from his primary task(s). Finally, we urge frequentreview of callout procedures: as other procedures change, callouts should be reexamined.6.4 PROCEDURAL DEVIATION DURING AN ABNORMAL SITUATIONThe discussion up to this point has focused on procedure deviation during normal operations. There areprocedure deviations during emergencies too. The topic of procedures, in general, always brings aboutthe question of when is it permissible to deviate from them. Is it permissible to deviate from a lowpriority procedure (e.g., after takeoff checklist) when, due to high workload induced by an abnormalcondition (electrical failure and a IFR missed approach), it cannot be performed (Wiener et al. 1991)?The answer is clearly “yes:” procedures were designed remotely from the situation at hand, andoccasionally it is necessary to deviate from a procedure. As we have said before, procedures are in placeto aid pilots, not to enslave them.It is the nature of any goal-oriented system that the system goal, e.g., making a safe landing/evacuationfollowing a malfunction, is always highlighted, not the process by which it is achieved. We assume thatif the process is valid, then the result will be too. But that assumption is not always true. If a pilotdeviates from procedures, training, policies, or even regulations, but saves the day, he or she is a hero,and there is a lot of talk about the flexibility of the human. On the other hand, if the pilot fails, he or shecan be charged for deviation from basic operating procedures and discredited, or worse.This paradox will always exist in any goal-oriented system, particularly if it operates in a dynamic andtightly coupled environment. Therefore it is important that management make a stand on this paradox viapolicies and philosophy. We have previously stated that one goal of management is to minimizedeviations from procedures. In an emergency, such deviations must be accepted. The following ASRSreport speaks to that issue and summarizes, via an example, the discussion of this chapter.While cruising at FL280, the left engine flamed out. Two unsuccessful attempts were made to restart theengine. Aircraft was landed at Cedar Rapids Airport 13,000 pounds over weight (143,000 pounds gross weight).The time elapsed from engine failure to landing was almost 30 minutes. During that time, the workload on a 2-person cockpit is tremendous. Communication with ATC, flight attendants, passengers, and each other, leaveslittle time for through analysis of aircraft problem itself. Our checklists are more directed to engine failure attakeoff, or shortly thereafter, with almost no guidance on priorities at altitude. So many books to check forsingle engine altitude, drift down speed, failure checklist, maximum over weight, landing weight for runwayavailable, restart checklist, and normal checklists. Although I had my own written [italics added] rough guide forthis situation, I found it necessary to revise many items in light of my experience. (ASRS report no. 216283).We pass now from principles of procedure design, and factors that must be considered, to a discussionabout the task of designing procedures. Chapter 7 lays out an orderly, comprehensive method for theactual construction of the procedures, and in Section 7.4 the implementation of procedures, somethingwe have not emphasized in previous chapters. The difficult question of standardization, both within andacross fleets, is attacked is this chapter. Numerous examples from database searches and from our ownexperience in the jumpseat illustrate the points.40