The Boeing 737 Max reintroduction to service has been the outcome of extensive testing and modifications. The flight standardisation board has issued a draft report REV17. There are training requirements for both Pilots and engineers. The requirements for the pilots however seem to be much more in comparison. FAA conducts a detailed analysis of the training requirements which is based on the FAA AC120-53B. I am sure that the compliance has been doubly checked and with a higher level of scrutiny with the whole globe waiting for the final outcome. I did read the training report and it made me wonder about where was the Human Factor part addressed in the entire re-entry to the service process. HF seems to be devoid of the importance that it was given when the accidents happened.
Pilots left to their devices
The recent major accidents have brought the attention of the designers and investigators to the issue of pilot’s handling of automation. Interestingly, there is no single strategy to deal with it or train a pilot to handle the situation. The B-737 Max training includes:
Multiple flight deck alerts during non-normal conditions. Training must include scenario-based training where a single malfunction results in multiple flight deck alerts that require timely pilot actions to include recognition and interpretation of the non-normal condition and prioritization of the required pilot actions. This training must be included in initial, upgrade, transition, and recurrent training.
It may sound very simple and easy to implement but it has been seen in many situations how pilots react to ambiguous or non specific failure indications in high stress situations. The AirFrance 447 accident was the one which highlighted the need for upset recovery training and the handling of multiple alerts which do not unambiguously identify the cause of the technical failure. The two Max accidents were also due to multiple failure indications soon after takeoff in a highly stressful environment.
A NASA Study found that the probability of responding correctly for non-trained aircraft emergencies was only 7%, as compared to highly trained “textbook”emergencies at 86%. The Human Factor Endsley testimony on the B-737 Max accident has stated the following:
While alarms and alerts are a key method for helping pilots to detect and diagnose system failures, they were of little help in these accidents. Response to system alerts is not always automatic and immediate, contrary to the stated design assumption of 3 seconds.Responses to alarms and alerts area affected by many factors including the salience of the alert for gaining attention, form of presentation, agreement/disagreement with other indicators, and prior experience with the alert.People must also interpret the meaning of alarms, which depends on context, their mental model of what is happening, and expectations. Often people seek to confirm alarms, and need additional time to properly diagnose the meaning of the alarms in order to select appropriate actions. For example, Boeing’s own data on controlled flight into terrain accidents over a 17-year period show that 26% of these cases involved no response, a slow response, or an incorrect response by the pilot to the GPWS alarm.
The reintroduced B-737 Max cannot be dispatched with both AutoPilots inoperative. This is probably a mitigating measure for deactivating the infamous MCAS which stops the moment the AP is switched ON. This may be a sound technical resolution or a mitigating measure but the Boeing automation philosophy trains the pilots to switch OFF automation. In keeping with this guiding principle, in most other Boeing aircraft the pilot can always easily resume control by shutting off the autopilot system. However, this exception is only for the Max.
The brain forms a habit in about 66 days of regular practice. The decision is to keep the AP ON under certain situations based on pilots, interpretation of the situation and proxy indications. This means that the pilot will recognise the multiple failures, assess the situation and then react. The reaction under a highly stressful situation must be counterintuitive. This requirement can only be achieved by highly trained pilots. This situation is similar to a stall where the pilots is expected to reduce the angle of attack typically by pushing the control column forward with the aircraft loosing height rapidly. The industry is spending billions of USD to train the trainers and pilots.
Who will bell the cat?
FAA has issued directions that the training requirements in the FSB Rev17 are applicable for US air carriers and US registered aircraft. Other regulators must devise their own strategies. Human Factor and training is the key here and has been in focus for a long time. However there needs to be a consensus amongst all to devise a strategy.
If we look at the history of automation development, the B-737 200 series was considered an ideal aircraft for manual flying and a sturdy aircraft. The introduction of the fly by wire in the A-320 during the late 1980’s changed the game. While the pilots were comfortable with manual flying and trusted their skills, Airbus wanted the pilots to use maximum automation. The Engine failure at take off highly recommended the use of automation to reduce stress.The pilots would switch OFF automation post a technical failure but this habit was changed over a period of time and they began trusting automation and used the automation till the limits.
Soon the accidents started taking place due excessive reliance on automation. The pilots no longer trusted their skills and assumed that the automation would know better and handle the situation safely. The OEM’s changed their tone and put out in bold letters that the pilot must use optimum level of automation and revert to manual flying when things don’t seem right. OK, everyone now though that this was the answer till AF447 and the two Max accidents. Now there are contradictions within the philosophy.
The Stab trim in the Boeing requires brute force to hold the control column acting against aerodynamic loads. A recent study by the FAA found that over 60% of females and between 15 and 65% of males (depending on age) were unable to meet current FAA code requirements for short term force application. Further, 10 pounds of force for yoke pitch and stick pitch(the long term requirement)could be maintained for less than 5 minutes by between 42% and 60% of females and 12% of males.
In addition to cognitive stress, the pilots are under physical stress too. Proxy indications are which do not give an unambiguous indication. The pilot is expected to interpret the situation based on assessing multiple parameters. A case similar to a unstable approach where the pilot must monitor speed, rate of descent, configuration… There is no single light akin the GPWS or TCAS which gives clear indications for implementation of procedures.
The MAX training requires the pilot to interpret the situation by assessing multiple failure indications, keep the Autopilot ON under some situations and OFF during others. Thereafter while using brute force to control the aircraft, the pilot is expected to use their cognitive skills to use either memory actions or a written checklist action.
- Provide automation reliability
- The user should be in command
- Provide automation transparency
- Provide training to users on automation to ensure adequate understanding and appropriate levels of trust
- Avoid increasing cognitive demands, workload and distractions and make tasks easy to perform
- Make alarms unambiguous
- Support the diagnosis, management, and assessment of multiple alarms
NTSB in their recommendations has stated that as previously discussed, Title 14 CFR 25.1322 addresses flight crew alerting and states, in part, that flight crew alerts must
(1) Provide the flight crew with the information needed to:
(i) Identify non-normal operation or airplane system conditions, and
(ii) Determine the appropriate actions, if any.
(2) Be readily and easily detectable and intelligible by the flight crew under all foreseeable operating conditions, including conditions where multiple alerts are provided.
The NTSB recommends that the FAA develop design standards, with the input of industry and human factors experts, for aircraft system diagnostic tools that improve the prioritization and clarity of failure indications (direct and indirect) presented to pilots to improve the timeliness and effectiveness of their response. The NTSB further recommends that once the design standards have been developed as recommended in Recommendation A-19-15, the FAA require implementation of system diagnostic tools on transport-category aircraft to improve the timeliness and effectiveness of pilots’ response when multiple flight deck alerts and indications are present.
Regulators and HF experts
Regulators with HF experts need to take a tough call in the public interest regarding the reintroduction of the B-737 Max into service. The Human Factor part has not been adequately addressed by FAA despite NTSB recommendations. The training of pilots for handling complex scenarios needs an industry debate to come up with a joint strategy back by science. The issue must be taken up by regulators and public at various levels.