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

7.5.1 Cross-fleet StandardizationCross-fleet standardization is an economic (and sometimes emotional) topic that involves complex tradeoffs,and often has no easy solution. If done properly, cross-fleet standardization provides for smoothtransition from one aircraft to another, and a solid framework for training, checking, and line flying.During our visits to the airlines, we attended such standardization meetings. In one meeting, the agendaitems was the cross-fleet consistency of the DESCENT, APPROACH, and LANDING checklist withrespect to the altimeters check.The problem was that in Europe, the transition altitude varies from nation to nation and can be as low as FL 40.Likewise, in some parts of the Caribbean (where U.S.-operated domestic narrow body aircraft also fly), thetransition altitude is lower then in the U.S. The procedural dilemma was how to implement a procedure thatchecks that altimeters are set to QNH during descent into the terminal area.The first alternative was to have all aircraft check altimeters at 18,000 feet (note, however, that this is anunnecessary check when the transition altitude is below 18,000 feet). The second was to have all aircraft checkaltimeters with the APPROACH checklist (which is conducted below 18,000 feet) to “cover” those aircraft thatfly to the Orient were transition altitude may be somewhere between FL 140 and FL 80. This would add a“nuisance” checklist items to the domestic narrow body aircraft). The third was to have all aircraft checkaltimeters with the LANDING check to cover all those aircraft that are landing in Europe. The effect of thisstandardization would be to add two “nuisance” checklist items to the domestic narrow body fleets.The final solution was to list altimeters checks in the DESCENT and APPROACH checklist only. Thealtimeters check was to be written as the last item on the APPROACH checklist, and a to go item was to beallowed. When the APPROACH checklist is performed above the transition altitude, the PNF will say“altimeters to go” and wait until the transition altitude is reached in order to complete the APPROACHchecklist.The benefits of cross fleet standardization are quite obvious. And there are vast areas in cockpitoperations where this can be done properly (mainly in the non-aircraft specific procedures, e.g.,precision/non-precision profile callouts, and many more). Nevertheless, it is not always possible. Ifdone improperly, it may lead to sub-optimal procedures by superimposing procedures that are suitablefor one type of cockpit operation on another. This kind of cross-fleet standardization may turn out to bea very expensive will-of-the-wisp.Part of the altitude verification procedure described in Section 5.7.2 is also illustrative of a trade-off in designingcross-fleet procedures. This procedure specifies the duties, with respect to manipulation of controls between thePF and PNF, as a function of the level of automation used: hand flying (PNF manipulates the MCP controls) orautopilot operation (PF does so). This procedure was generic to the extent that it could be used across all fleets,with exception, however, of the DC-9 fleet.In the DC-9 cockpit, the location of the altitude alerter is adjacent to the F/O's left knee. It is difficult for thecaptain to access, set, or read its numeric display. Therefore the procedure for the DC-9 fleet is different fromother fleets: the F/O always sets the altitude alerter, regardless of whether he or she is the PF or PNF. Anentire cross-fleet standardization could be not be achieved -- the price was just too high.Inappropriate standardization may therefore interfere with the intelligent exercise of piloting tasks(Johnston, 1991). In such cases, the flight crews are the ones who have to bear the consequences of thisincompatibility. We therefore argue that the airline must develop a philosophy for cross-fleetstandardization. Such a philosophy can help draw the line between reasonable and unreasonable crossfleetstandardization efforts. This will allow the designer a frame of reference with regards to suchprocedures. Once communicated to all, the standardization philosophy may allow other persons (such asinstructors, IOE and line check airman, FAA inspectors, and line pilots) to better understand, critique,and check such procedures.An additional measure for improving standardization efforts is creating a formal cross-fleet forum (suchas one company’s fleet captains’ board). This forum, which includes the lead captain from every fleet inthe airline, meets regularly and is the only entity that approves such procedural changes. The fact thatany procedure change must be approved by all fleet captains, enhances coordination and minimizes the50