In a recent post Julien mentioned that he prepared “flow patterns” to help him getting familiar with the Arrow he’s now training on. Flow patterns have been developed in commercial aviation but apply well to light, private aviation as well. This also has to do with checklists and memory items. Most private pilots use checklists as “do-lists”. The two last FTOs I trained with make the difference because they are mostly training professional pilots to be. The difference between do-lists and checklists is quite easy. Do-lists are used to guide actions as they are getting done. Checklists are used to verify actions previously done on base of memorised items.

The idea is to avoid constantly switching attention from the checklist to the cockpit element to be switched, twisted, flipped, pulled or pushed. Not all series of items can be verified, at least in single pilot operations, i.e. the final check (at least: gear – flaps – light, and if applicable: carburetor heat – high RPM – cowl-flaps). Hopefully this one is short. The longest lists are usually the before descent check (at least in IFR) and cockpit preparation before start-up. The DA42 one contains not least than 21 items. Shall the pilot memorise all of them to apply the do-list / check-list principle ? Yes. And this is where flow patterns come into the game. Some lists are built on a system oriented base: all electrical, all fuel, and so on. Flows are based on cockpit to make them easier to remember.

Flows are not always logical in terms of sequence but they are made to be easy to remember. The picture below shows the sequence of items in Diamond’s cockpit preparation checklist for the DA42. Thanks to good cockpit design it’s almost easy to remember. Not all cockpits are so well designed and some are even anti-ergonomic.

This flow starts on the parking brake on the center pedestal. Even if it’s not so bad it’s still looping and jumping around. The FTO I fly with developped a much easier flow pattern based on the very natural reading direction (except for asian languages…) from left to right and top to bottom. It starts top left with the lights and then goes to the right, then back left “one line below” with the ECU and alternator switches, to the right, and so on…

This flow pattern makes it easy not to miss any item. I can’t cite all of the 21 items but simply “scanning” the cockpit makes it easy. Once the flow is completed the checklist is used to verify that no item was left unchecked. It’s that easy.

Do-lists (read memory items) can also rely on flow pattern to make them easier to memorize. On the DA42 the following items must be performed on engine failure once the failed engine is correctly identified: engine master off – fuel selector off – alternator off. The engine master is right in front of the pilot, on each side of the key, the fuel selectors are on the central pedestal (where the two red locks can be seen), and the alternator switches are on the left-hand side of the panel, below the fresh air outlet. Once the engine is stopped there is no system reason to first close the fuel valve before getting the alternator online. My personal variant of this drill is: engine master off – alternator off – fuel selector off. I find much easier to first get the alternator offline as this switch is much closer to the engine master than the fuel selector.

One must take great care when modifying the checklists proposed by the aircraft manufacturer. In this example it could be “geometrically” tempting to use the following sequence: fuel selector off – engine master off – alternator off, but this would damage the engine, particularly if done for training purposes. Diesel engines uses high pressure pumps that can be damaged if they run out of fuel… Damaging one while practicing an incorrectly adapted drill would be a shame.

You can read more about how airlines use checklists, do-lists and flow patterns and how to possibly adapt them to your flying from this excellent post from Sam.