Muscle memory

MUSCLE MEMORY #2

From NASA ASRS CALLBACK Issue 434
NOTE: The plane on the photo is not related to the incidents narrated  here

Photo: © Lars Veling http://www.airplane-pictures.net/photo/684945/g-ezug-easyjet-airbus-a320/

THE BEST LAID PLANS…

Even when the need for a non-standard sequence of events is recognized and planned for in advance, strong muscle memory concerning the standard sequence can prevail. This CRJ200 First Officer confirms that slowing down is the best way to engage the brain and disengage muscle memory.

■ When we received the aircraft, the previous crew had written up the #2 AC Generator. Maintenance came and deferred the generator. Per the MEL operations instructions, we were to keep the APU running for the entire flight. The Captain and I discussed this as part of our pre-departure briefing. When Tower cleared us to line up and wait, I ran the Takeoff Checklist and turned off the APU out of habit. I realized my mistake and informed the Captain. We notified the Tower that we would need to exit the runway and get back in line to restart the APU.

This incident illustrates why it is important to slow down when completing checklists and flows during abnormal operations to ensure they are completed properly. I shutdown the APU due to “muscle memory” during the Takeoff Checklist even though we had discussed the MEL procedures for the deferred AC Generator during the pre-departure briefing.

ROLLING IN THE SNOW

A CRJ900 Captain, faced with an oncoming snow plow, went for the brakes and engine reverse, but muscle memory had other ideas.

■ After landing, we were taxiing to our gate. The taxiways were snow covered with fair braking action. We had shut down our right engine and left the APU shut down. A snow plow was on our right and just ahead of us. I was watching him when he abruptly started to turn left into us. I applied the brakes, with minimal effectiveness, and I was going to apply reverse thrust, but muscle memory kicked in and I mistakenly shut down the left engine. We lost all power and rolled to a stop. The plow never completed his turn, but saw us and turned away. We informed ATC and started the APU to restart an engine. Within two minutes the engine was running again and we taxied to the gate without incident.

ARMED AND DANGEROUS

An A320 First Officer got a first-hand lesson in how a busy, rushed environment can cause muscle memory to override a more methodical thought process.

■ This incident started about 5-10 minutes after the last passenger deplaned. Doors 1L and 2L were both open. There were many cleaners on the aircraft from the front to the back. The situation was busy at best, frantic at worst. I was standing on the front air stairs when a Flight Attendant asked me if I could supervise the opening of Door 2R. The cleaners were beating on the door to have it opened so that the trash could be emptied. I agreed to supervise since no other crewmembers were available. I followed the Flight Attendant to the back of the airplane where various ramp personnel were in the aft galley conducting their work. The Flight Attendant proceeded to arm the door as it had been disarmed from deplaning. It was at this point that I became confused. Before I could intervene, the Flight Attendant pulled up on the handle. The door opened and the slide blew. Luckily, no one was injured.

I should have done a better job confirming what was actually going on and tried to slow the process down.… The overall issue for me was being distracted, rushed and uncertain of my supervision objective. I also believe the Flight Attendant was trying to do the right thing, especially as a new employee. She was rushed and getting pressure from the cleaners. In retrospect, I think she was operating on muscle memory. Since she had already disarmed the door, the next event was to arm it.

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Our cognitive processing begins with selecting an event and maintaining it in our consciousness. The event may be internally generated (thought) or initiated by internal or external stimuli. Given the great number of stimuli impending on our sensory systems at any moment in time, we must select events or stimuli for further processing. To accomplish this, we selectively “focus on” and “attend to” specific stimuli that are most relevant to our purpose.

However, our attention resources are limited. Wickens in his model uses the analogy of a resevoir that is part of a closed system with a “set” amount of attentional resources. When attentional resources are expended on one component of the information processing system, less remains for use by the other components.*

Attention

Selective focusing or “attention” determines what information is transmitted to working memory. The amount of stimuli that can be taken in by our sensory systems is considered to be unlimited. However, the amount of information that can be held in working memory is limited to 7 + 2 items for 18 to 20 seconds.* Working memory, therefore, creates a “bottleneck” for incoming information. In a sense, it is a “bottleneck” with a purpose–otherwise, we would be inundated with irrelevant stimuli. Attention is also influenced by:

• Expectancy – We direct our sensory receptors–eyes, ears, nose, fingertips–to where we anticipate locating information within our environment. Surprise occurs when events differ from our expectation.**
• Relevance – We seek information/stimuli relevant to our immediate tasks and our goals.**

*Miller, G., “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information,” The Psychological Review, 1956, vol. 63, pp. 81-97.
** Wickens, C.D., “Attention to Safety and the Psychology of Surprise,” Keynote address: 2001 Symposium on Aviation Psychology: Ohio State University.
***Values for the duration of sensory and short-term memory will vary by study & researcher.

Attention Control – Our attention constantly shifts as a result of voluntary direction (internal) or automatically as a result of attention attracting stimuli (external) in the environment. Our focus of attention results from whether a stimulus activates Top-Down (internal) or Bottom-Up (external) processes.

• Top-Down – Attention control is under conscious direction, using information residing in memory stores. It is also termed concept driven or effortful attention. Top-Down attention is purposefully directed and is influenced by expectancy and relevance, as well as prior knowledge and experience. Examples are a search task such as when looking for the face of a friend in a crowd, seeking a specific item on a control display, or concentrating on performing a task. Top-down attention is slower than bottom-up attention.*
  
• Bottom-Up – Attention is captured by external stimuli, usually unexpected events. This is also termed data driven or automatic attention. Examples are a bright flash of light, a loud sound, loss of balance due to slippery conditions, or impact by an object. Bottom-up attention is very rapid, reaching its maximum 100-200 milliseconds after stimulus perception.****

****Taylor, J.G., “Recent Advances in Understanding Attention,” Science & Consciousness Review, 2003, on-line.

Divided and Sustained Attention

Task and interface design need to consider other attentional aspects of human functioning. Many tasks require divided attention, that is, sharing attention among several aspects of the environment. Driving is a divided attention task, as is piloting an aircraft. Other tasks require sustained, concentrated attention to detect small changes in displays or control panels. Examples are air traffic control and nuclear power plant monitoring.

• Divided Attention – Defined as the ability to perform more than one task at a time. The ability to perform these tasks successfully depends in part on the nature of the tasks and whether or not they use the same or different cognitive processes. If the tasks draw upon different processes there is a higher likelihood that the tasks can be successfully performed concurrently. If the tasks require use of the same cognitive processes, it is less likely the tasks will be performed within acceptable time and accuracy parameters. The more similar the tasks, the more difficult it will be to perform them simultaneously. Also, the more difficult the tasks, the harder it will be to perform then simultaneously, although this may be somewhat ameliorated by practice.*****
• Sustained Attention – Sustained attention requires concentrating on one primary task for a long period of time while remaining alert to changes. With the increased use of automated systems, many jobs have changed from “active doing” to monitoring or “supervising” systems. Unfortunately, humans are notoriously poor at these types of tasks. It has been consistently found that human performance quickly deteriorates over time such that “vigilance decrement” is a common term in research.

***** adapted from Burnett, G. E, 2003, University of Nottingham

The previous paragraphs were excerpted from FAA Human Factors Awareness Web Course

FURTHER READING

1. “To my horror… I unintentionally shut down the number two engine as well….” Muscle memory #1

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By Laura Victoria Duque Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day 

 

“To my horror… I unintentionally shut down the number two engine as well….”

MUSCLE MEMORY

From NASA ASRS CALLBACK Issue 434
NOTE: The plane on the photo is not related to the incidents reported here

Muscle memory is an interesting physiological phenomenon involving our muscles and their interaction with the brain. The more often we perform a given physical action, the more likely we are to do it as needed, when needed, without having to think about the specific combination of movements involved. These habits thus become an unconscious process that occurs when triggered by a given circumstance or set of cues.

Practicing a procedure until the process is automatic develops muscle memory that can be crucial when an immediate action emergency (such as an engine failure at V1) occurs. However, as in the incident reports below, muscle memory can be a problem when the cues are right, but the circumstances are wrong. That is when the brain has to be “conscious” enough to stop the automatic response of well-trained muscles.

The following ASRS reports recount a sequence of ground incidents in which muscle memory took over at the wrong time.

Photo: http://www.privatejetcharter.co.uk/aircraft-type/boeing/boeing-737

TAXI OUT, TOW BACK
Faced with a distraction and a familiar set of circumstances, a B737 Captain let muscle memory take over just long enough to create an embarrassing situation.
■ Inoperative APU; second flight of the day; started the number one engine at the gate…; asked for taxi to a remote area for cross-bleed start of the number two engine. Stopping at the designated location, the aircraft began to shimmy slightly under braking. I stopped braking then applied brakes again. The shimmy did not happen again so I set the parking brake. I then grabbed the number one engine start lever and began to shut the number one engine down. Realizing what I was doing, I quickly returned it to the previous position, but the engine had already shut down. We were now on battery power. I told the Flight Attendants to remain seated, then told ATC we would need a tow back to the gate and we had one radio and would need to go off frequency to coordinate with Company Operations. We turned IRS 1 and 2 off and tried to explain to the passengers what had happened. We were back at the gate in approximately 10 minutes. We started the engine and did the procedure properly the second time. The remainder of the flight was uneventful.

I guess I would say it was muscle memory, the same motion as arriving at a gate, number two engine shut down, parking brake set. I should be more deliberate in all of my actions, but it happened so fast that the First Officer did not even have time to react. The brake shimmy was a distraction, but that does not excuse me from my action.

A BAD MATCHUP
This B737 Captain’s method of checking the start lever position was problem enough, but then muscle memory kicked in and made the situation worse.
■ It was my leg. Preflight activities had been normal and we were not rushed at all.… We had been instructed to hold short of [the runway] and were almost stopped. I had already called for the Before Takeoff Checklist and the First Officer challenged me with “Start Levers” at the next to last step in that checklist. I reached down to confirm “Idle.” My practice has been to hold the start levers with my thumb and forefinger, confirm the idle detent position with a slight nudge forward and a slight nudge rearward, then to respond, “Idle.” However this time with the slight nudge to the rear, the number one start lever felt like it was not quite fully down in the idle detent. It came up over the edge and I unintentionally shut down the number one engine. I was surprised and stunned.

I announced the situation to the First Officer and set the parking brake. Then instinctively I reached down again to confirm the start lever positions. At that point muscle memory kicked in and I must have “matched” the start lever heights. To my horror, when I nudged the levers rearward again, I unintentionally shut down the number two engine as well. I started the APU and put electrical power back on the aircraft. We told ATC that we had a problem and that it would be a few minutes before we could move. Feeling completely inept and embarrassed, I told the First Officer that we would start over and re-accomplish everything beginning with the Before Start Checklist. The First Officer agreed.

I made a short and embarrassing announcement to the Passengers and apologized for the delay while we dealt with a cockpit issue. We then flew an otherwise uneventful flight. Several suggestions come to mind in order to prevent this from happening again. Primarily, I have changed the way that I check the start levers in the idle detent. No longer will I hold them with my thumb and forefinger. And no longer will I nudge them rearward, but only forward and down.

HOUSTON, WE HAVE “AN ISSUE”
A B737-800 Captain’s prescription for inhibiting muscle memory involves slowing down and thinking before a particular situation triggers your internal automation and results in a dose of humility.
■ We were told to line up and wait. I brought the aircraft to a stop and, for some strange reason, I reached over and shut down both engines instead of setting the parking brake. We told Tower that we had an “issue” and would be in place for a minute or two and then we would have to taxi clear. We started the right engine and taxied clear of the runway so we could redo checklists and regroup. When the Tower later asked what our issue was, I think we told them that we had to look at a light. Actually, lots of lights.

With the start levers being right next to the parking brake, I guess that once my hand was on the start levers, positioned right next to the parking brake, muscle memory took over and moved them to off. I need to slow down and think about what I am doing before moving any switch or lever. This was definitely the healthiest dose of humility ever in my many years of flying.

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Automatic Response

Automaticity is one of the by-products of practice. As procedures become automatic, less attention is required to carry them out, so it is possible to do other things simultaneously, or at least do other things more comfortably. (FAA-H8083-9A)

The first mental process of safe flight is AUTOMATIC REACTION. Automatic reaction is used to maintain ongoing control of the aircraft, such as stabilizing heading and altitude by making small, automatic adjustments to the controls. It may also be used in certain emergency situations where specific, prompt action is required.

Pilots learn to do many things automatically, simultaneously, and without thinking about each individual act. They have learned skills and procedures that are now more or less automatic reactions for them. When they first practiced them, however, they had to devote a great deal of their attention to them and concentrate in order to perform successfully. Gradually, with more practice, there was a decline and eventual elimination (possibly without their realization) of their need to “think about” what they were doing as these skills became truly automatic reactions. (DOT/FAA/PM-86/45)

When skills are learned to the point of automaticity, the load on working memory typically is reduced by 90%. Typically, skills learned to the point of automaticity are also difficult to describe.

During Skill Acquisition	After Skill Automaticity
fMRIs – Differences in Brain Activation Transition from Working Memory & Attentional Control to Sensory & Motor Processing*

*Schneider, W. (2003), “Automaticity in complex cognition,” Center for Cognitive Brain Imaging at Carnegie Mellon University.

Tasks learned to the point of “automaticity” are not easily changed by conscious control.

 

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By Laura Victoria Duque Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day 

 

Germanwings accident final report published

Accident to the Airbus A320-211, registered D-AIPX and operated by Germanwings, flight GWI18G, on 03/24/15 at Prads-Haute-Bléone.

N° BEA2015-0125.en

Synopsis

Deliberate flight into terrain

Photo (C) Dejan Milinkovic – Pixstel Photography Airliners.net

Aircraft	Airbus A320-211 registered D-AIPX
Date and time	24 March 2015 at 09 h 41(1)
Opertor	Germanwings
Place	Prads-Haute-Bléone (04)
Type of flight	Commercial Air Transport Revenue operations, Passenger
Persons on board	Captain (PM), co-pilot (PF), 4 cabin crew, 144 passengers
Consequences and damage	Crew and passengers fatally injured, aeroplane destroyed

The co-pilot had been flying for Germanwings since June 2014 and was the holder a class 1 medical certificate that was first issued in April 2008 and had been revalidated or renewed every year. Since July 2009, this medical certificate had contained a waiver because of a severe depressive episode without psychotic symptoms that had lasted from August 2008 until July 2009. This waiver stated that it would become invalid if there was a relapse into depression.

In December 2014, approximately five months after the last revalidation of his class 1 medical certificate, the co-pilot started to show symptoms that could be consistent with a psychotic depressive episode. He consulted several doctors, including a psychiatrist on at least two occasions, who prescribed anti-depressant medication. The co-pilot did not contact any Aero-Medical Examiners (AME) between the beginning of his decrease in medical fitness in December 2014 and the day of the accident.

In February 2015, a private physician diagnosed a psychosomatic disorder and an anxiety disorder and referred the co-pilot to a psychotherapist and psychiatrist. On 10 March 2015, the same physician diagnosed a possible psychosis and recommended psychiatric hospital treatment. A psychiatrist prescribed anti‑depressant and sleeping aid medication in February and March 2015. Neither of those health care providers informed any aviation authority, nor any other authority about the co-pilot’s mental state. Several sick leave certificates were issued by these physicians, but not all of them were forwarded to Germanwings.

No action could have been taken by the authorities and/or his employer to prevent him from flying on the day of the accident, because they were informed by neither the co-pilot himself, nor by anybody else, such as a physician, a colleague, or family member.

In the cruise phase of the accident flight, the co-pilot waited until he was alone in the cockpit. He then intentionally modified the autopilot settings to order the aeroplane to descend. He kept the cockpit door locked during the descent, despite requests for access made via the keypad and the cabin interphone. He did not respond to the calls from the civil or military air traffic controllers, nor to knocks on the door. Security requirements that led to cockpit doors designed to resist forcible intrusion by unauthorized persons made it impossible to enter the flight compartment before the aircraft impacted the terrain in the French Alps.

The BEA investigation concluded that the process for medical certification of pilots, in particular self-reporting in case of decrease in medical fitness between two periodic medical evaluations, did not succeed in preventing the co-pilot, who was experiencing mental disorder with psychotic symptoms, from exercising the privilege of his licence. The following factors may have contributed to the failure of this principle:

..the co-pilot’s probable fear of losing his right to fly as a professional pilot if he had reported his decrease in medical fitness to an AME;

..the potential financial consequences generated by the lack of specific insurance covering the risks of loss of income in case of unfitness to fly;

..the lack of clear guidelines in German regulations on when a threat to public safety outweighs the requirements of medical confidentiality.

The BEA has addressed eleven safety recommendations to the WHO, IATA, the European Commission, EASA, BMVI and BÄK relating to:

..medical evaluation of pilots with mental health issues;

..routine analysis of in-flight incapacitation;

..mitigation of the consequences of loss of licence;

..anti-depressant medication and flying status;

..balance between medical confidentiality and public safety;

..promotion of pilot support programmes.

To download the complete final report (French, German, English and Spanish) go to the BEA site Accident to the Airbus A320-211, registered D-AIPX and operated by Germanwings, flight GWI18G, on 03/24/15 at Prads-Haute-Bléone.

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By Laura Victoria Duque Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day