• What Do We Do Now? Decision Making on the Flight Deck


    skelsey

    By Simon Kelsey
    Contributing Editor

     

    Whoop whoop whoop. I frowned as the yellow Master Caution lights blazed in to action on the panel in front of me, a string of warning messages appearing on the Boeing 747-400’s central display screen.

     

    We were on a late downwind for runway 02L at Singapore’s Changi Airport. Outside the Perspex flight deck windows sunset was fast approaching, the temperature nudging thirty degrees Celsius in thick, sticky tropical air, but beyond the garage that housed the full-scale 747 flight deck in which we were sitting it was about half past nine on a crisp November morning with a light frost on the grass. Both myself and Dan, in the left-hand seat for this leg, had been up most of the night putting in stints in various crew positions as Worldflight 2016 gradually wended its way around the globe.

    I was flying the approach for Dan’s landing, standard practice at British Airways. The VATSIM Singapore controller -- his voice crackling in to our headsets from halfway across the globe -- had just given us a turn on to base leg, and I’d asked for flap 10, which was where the problems started.

    ‘Flaps Drive,’ read Dan off the screen, already reaching for the Quick Reference Handbook (QRH) that lives in a slot in the flight deck just underneath the side window, so that it is immediately available in any situation. The QRH is a thick, spiral-bound booklet which contains details of every fault and warning message the aeroplane is capable of generating, each with a checklist to be completed.

    ‘OK, my radios - if you could do the Flaps Drive QRH please.’

    Dan started leafing through the QRH. The first rule in any non-normal situation is to fly the aeroplane: as Pilot Flying that was my job first and foremost, so I had a quick scan of the instruments, making sure that the autopilot was still engaged, everything was stable and we were still going in the right direction. Once I was satisfied that the flight path was safe, my thoughts turned to how we would manage the problem.

    Flaps Drive QRH pageWe can all think of times when we’ve made poor decisions in life, perhaps because we were rushed, under pressure or simply didn’t take proper account of all the details.

    In the flight deck, however, rushed or ill-thought-through decisions are simply not an option. In an era in which almost 80% of accidents can be traced back to human error, poor judgement and poor decision making consistently rank in the top five causes of fatal airline accidents.

    Commercial pilots are trained to use ‘decision-making models’. These are frameworks, acronyms such as ‘PIOSEE’, ‘NMATE’ or ‘GRADE’ to name but a few which you may already be familiar with, designed to ensure that decisions are well-considered and properly informed.

    British Airways uses a system called ‘DODAR’, which stands for Diagnosis - Options - Decision - Act (or Assign) - Review. Commonly a ‘T’ (for ‘time’) is added as the first item, to give ‘T-DODAR’.

    Time is considered first, because the options available are often directly dependent on the level of urgency. Outside of a fire or a medical emergency, there are very few situations where it is not better to either take or make more time to ensure the correct decisions are taken.

    In the air, fuel is time. I tell my students to stop thinking about fuel in terms of volume or mass, and instead start thinking about it in terms of time. We had about twelve tonnes of fuel on board -- in a 747-400, that gives you about forty-five minutes airborne before you start eating in to your final reserve.

    The Flaps Drive non-normal checklist is a long one, running to several pages in the QRH. I didn’t want us to have to rush through the checklist whilst barrelling down the approach -- and, even worse, Dan’s capacity to monitor my flying would be severely diminished if he had his head buried in a book. After a brief fuel check, we agreed that we should make ourselves some time to deal with the flap problem by going around and entering a hold.

    Diagnosis involves finding out what is wrong and what might be causing it. Whilst modern aircraft are generally quite good at telling you when they are poorly, it is vital to cross-check any alerts to ensure that you really are dealing with the right problem.

    Once the problem has been diagnosed, you can then consider your options. In our case, having decided to make some time to deal with the problem by going around and taking up the hold, we now needed to decide whether to attempt another approach at Changi or divert elsewhere. The other question was one of weight: had we had more fuel on board we might have considered holding or dumping fuel to further reduce our landing weight and therefore our approach speed.

    Both of these were fairly easy decisions to make. Changi was by far the most suitable airport for our situation, with three long runways, full ATC, plenty of facilities and perfect weather conditions. Weight would not be an issue either -- by the time we’d been round the hold a couple of times and made a second approach we’d be getting towards the point at which a diversion would be very tight anyway.

    Once the decision has been made, the next job is to act or assign tasks. In our case, we decided that I would carry on flying the aeroplane and speaking on the radio, whilst Dan worked through the checklist. Once the procedure was complete, we would revert to our normal roles, and finally Dan would take over at 1,000 feet as usual to complete the landing.

    The final step is review. The review is very important, and it is a continuous process. The plan Simon landing the Simfest B747-400 simulatormust constantly be updated as the situation changes and new information becomes available -- and this can be very fluid. Just as we thought we had everything just about dealt with and under control, a soft ping signalled a call from the cabin.

    A passenger was unwell, said the voice from ‘down the back’. A suspected heart attack.

    Of course, that added a new dimension to our hitherto calm and steady operation. Up until now, we’d essentially had all the time we wanted. This latest news changed that - now we needed to get on the ground without delay, yet still without rushing and taking unnecessary risks.

    Fortunately we had already completed the checklist for the flap problem, so after a brief discussion we advised Singapore ATC we were now ready to make an approach and that we had a medical emergency on board. Now pointed in the right direction, we quickly reviewed the situation: with reduced flap not only would our final approach speed be significantly higher than normal, the nose attitude would also be higher than normal, giving an unusual perspective. The aircraft would likely feel more sensitive in the flare, we would have a higher than usual rate of descent on final approach and we would need a higher autobrake setting and full reverse thrust to keep both landing distance and brake temperatures as reasonable as possible.

    The next question was how fast we should fly on downwind. Up until this point we’d left the speed where it had been when the failure first occurred - about 190 knots. Now, though, there was an imperative to shave off as much time from the approach as possible.

    With hindsight, we probably could have reasonably flown up to the Flap 10 placard speed of 240 knots. However, at the time we were both concerned that we didn’t want to place any more stress on the already jammed flaps than necessary, and so restricted our speed to 220 knots.

    Every flight is a sequence of decisions. Some are routine, some critical, some easily reconsidered, others irreversible. Of course, in some cases the use of a decision-making model is impractical -- one commonly-quoted example is that of QF32, where an uncontained engine failure resulted in such an overwhelming cascade of failures that it was impossible to methodically feed each and every one in to a DODAR-style framework.

    Likewise, some emergencies are so time-critical that a conscious optimised decision-making process is simply not viable: take, for example, flight BA38 and the decision of Captain Peter Burkill to retract a stage of flap in order to extend the aircraft’s glide just enough to avoid crashing in to houses just before the airfield boundary. In this instance, the decision-making model could be boiled down to a binary choice -- quite simply, ‘will it work?’ -- based on thousands of hours of experience and training, with no opportunity for discussion or collaboration. Such is the role -- and ultimate responsibility -- of the airline captain!

    There is plenty of opportunity to practice and improve your decision-making skills on every flight, but with the capability of modern add-ons to accurately simulate a wide variety of non-normal situations and generate ‘service-based’ failures, there is more scope than ever to put your thinking skills to the test (though do remember to take rules around declaring an emergency in to account if you are on a network like VATSIM or IVAO).

    As for the conclusion to our story? The VATSIM controllers at Singapore vectored us neatly round to the ILS, Dan took over as we descended through 1,000 feet and made a perfect landing despite a final approach speed nearly 30 knots faster than usual. Although the entire scenario had played out in a simulation and we had never left the ground for real, I think we were both fairly relieved when the engines spooled down at the gate!

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    User Feedback


    Brilliant piece, Simon. Food for thought what R/L aircrew can face, and it brings to mind AF447. T-DODAR.

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    Great article! I just added T-DODAR to the emergency documentation of our company, because it fits well outside aviation context, too. Let's see if it survives review :)

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