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Memory (Recall) Item Checklists

by Darren Smith, CFII/MEI
General Aviation Human Factors, Jan, 2009

Checklists: Intro to Memory Item Checklists | Criticism of Memory Item Checklists

Picture of Quick Reference Handbook, Boeing 737

Memory (Recall) Items are actions that must be performed very quickly in response to a failure that there is no time for reference to a printed checklist. Memory Item Checklists have been a long standing feature of air transport aircraft training programs and operations. Promulgated by airplane manufacturers, these checklists are committed to memory prior to a pilot's training on a given aircraft. For example, if you were hired at Southwest Airlines, you'd need to learn the memory items such as this one:

Engine Limit/Surge/Stall

Autothrottle........................................Off
Throttle..........................................Retard

Retard until indications remain within
appropriate limits or throttle is idle

In contrast, some airlines have developed checklists which do not require memorization and rely on Quick Reference Cards or flows followed-up by checklists. This is believed to allow flight crews to “cognitively process” the steps in such a checklist rather than execute them from long term memory. A sample of this from a major airline:

DO NOT RUSH
Aviation - Navigate - Communicate

Smoke, Flight Deck
     Oxygen Masks, Don, 100%
     Crew Communications Establish
          complete the steps in FCOM x.xx

Critics of Memory Item Checklists are concerned with human performance under stress. John Nance, noted aviation author says, "We used to have a lengthy list of Immediate Action items, all of which must be committed to memory - and the problem is that as many as half addressed situations that could be made worse by hurried knee-jerk responses. In order to slow everyone down where appropriate, those items were redrawn into the QRH checklists which we read as a challenge and response. There are really very few things that require an instant response using memory items other than flying the jet and keeping control, which does not need a checklist to accomplish."

Psychologists point to several factors to help pilots remember elements within Memory Item Checklists:

By far, the most important factor is the environmental que. If the right triggers are present, you'll retrieve the appropriate checklist from memory and then execute it. Otherwise, you're likely to execute the wrong checklist.
The next most important factor is the sheer number of memory items a pilot has to remember. When I first started learning large air transport aircraft, the CRJ 200 had 19 Memory Item Checklists. A survey of major airlines has yielded an average of 3 to 7 Memory Item Checklists.
Another important factor in correctly remembering checklist items is the complexity of the items within the checklist. In the case of the Memory Item Checklist above, it has 2 steps. The optimal number is no more than 3 items.
Finally, the situational factors of the failure, such as time available, threats, distractions, etc go a long way to preventing pilots from satisfactorily performing the items on a Memory Item Checklist.

The checklists that serve as the highest threat of degraded human performance are: aborted engine starts and uncommanded roll/yaw/pitch (Source: Dr Burian, NASA Ames). This has important implications to training programs if we want pilots to perform those Memory Item Checklists correctly. Sometimes, normal checklists are integrated into abnormal checklists and as such, pose greater risk/threat to pilots performing the tasks correctly and in sequence. Some of those procedures include:

some engine problems (e.g., Engine Failure and Shutdown)
some hydraulics problems (e.g., Manual Reversion)
some problems with flight controls (e.g., Jammed Stabilizer)
gear lever / gear problems (e.g., Gear Lever Will Not Move Up after TO)
Ditching

As such, training programs must ensure that pilots are adequately trained on these types of "jumps" among checklists. This becomes even more important when there are multiple jumps between abnormal, then normal, and finally another abnormal checklist.

What Do the Airlines Do?

Airline	Practice
American	Traditional Memory Item Checklists
Continental	Limited Memory Item Checklists (total of 2 with less than 3 items each)
Delta	Traditional Memory Item Checklists
United	NO Memory Item Checklists
US Air	Limited Memory Item Checklists

In the next article in this series, I will argue against Memory Item Checklists and their use in training programs and flight operations.

NEXT: Criticism of Memory Item Checklists>>

"When the weight of the paper equals the weight of the airplane, only then can you go flying."

— attributed to Donald Douglas (Mr. DC-n).

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