Flight Path Monitoring

Flight Path Monitoring

Definition

Flight path monitoring means the observation and interpretation of the flight path data, aircraft-configuration status, automation modes and on-board systems appropriate to the phase of flight. It involves a cognitive comparison of real-time data against the expected values, modes and procedures. It also includes observation of the other pilot and timely intervention in the event of a deviation.

This definition covers anytime the aircraft is in motion, including during taxi. It also includes continuous awareness of both the trajectory and energy state of the aircraft.

Description

Monitoring covers an extensive behavioural skill set that all pilots are expected to apply in the cockpit. The designated Pilot Flying (PF) is responsible for flying the aircraft in accordance with the operational brief and for monitoring the flight path. The Pilot Monitoring (PM) will have an explicit set of activities designated by the Standard Operating Procedures (SOPs) , and as such will have a specific and primary role to monitor the aircraft’s flight path, communications and the activities of the PF. Both pilots are responsible for maintaining their own situation awareness gained through cross-checking each other’s actions, communication of intent and diligent observation of the PF selections, mode activations and aircraft responses. Predictive monitoring supports anticipation of expected threats and the mitigation of consequences. Reactive monitoring enables the identification of unexpected/pop-up threats and mitigation of consequences; the detection and correction of errors; and the recognition of and recovery from undesired aircraft states.

Techniques

The cognitive processes engaged during monitoring are complex and involve the selective application of mental resources to encode the sensory inputs whilst performing a goal directed task. The senses relating to flight path monitoring are mainly visual and auditory, but tactile inputs from the flight controls (e.g. stick shaker, aeroplane buffet, etc.) can influence the monitoring task particularly in the event of a stall. Similarly, the smell and taste senses can alert the flight crew to fumes in the cockpit and therefore also perform a monitoring stimulus. Intent also forms an important part of monitoring and provides a baseline against which to monitor. Intent relates to system behaviour (what it is going to do), aircraft handling (predicted flight path/aircraft manoeuvrability) and Pilot Flying’s intent (the plan). Timely, accurate monitoring activities will result in outputs that, following crew judgement and decision making, can take the form of:

  • Verbalization to other pilot or self;
  • Non-verbal communication in the form of gesture/eye contact;
  • Note-taking in the case of auditory monitoring;
  • Reinforcement of collective situation awareness; and,
  • Maintenance of the mental model of the aircraft state.

Regarding physical ergonomics, pilots must be able to see and hear all information relevant to their monitoring tasks. Their seat positions must be adjusted to the design eye position to enable each pilot to view the internal displays and controls whilst maintaining an adequate view of the external scene. The optimal seat position is usually set by reference to two small balls on the central windscreen pillar. The balls appear aligned only when the pilot’s eye is at the design position.

Vision is a very complex subject and involves the ability of the eye to adapt to different lighting levels (called adaptation), focus on the information (normally referred to as accommodation) and to perceive information, such as texts and graphics, as legible at the required viewing distance (called visual acuity). Adaption, accommodation and acuity all vary with, and are affected by, age. Pilots need to be aware if they are experiencing any difficulty with focus, adaption or legibility of the displayed information as this will certainly compromise the monitoring task. Medical professionals will be able to advise on correction or treatment if necessary.

Hearing can be impaired by accumulation of wax in the outer ear (which is easily remedied), a head cold which blocks the Eustachian tube and prevents equalization of pressure or by infections in the middle ear. Hearing can be expected to deteriorate with age particularly with the higher frequencies. In addition, high ambient noise environment or distractions/interruptions in the cockpit can impact the clarity of aural messages. Under all circumstances, if there is any ambiguity related to information received aurally then ask for it to be repeated.

Barriers to Monitoring

Many factors hamper monitoring, including system and ergonomic design, organisational factors and external environment. But the biggest concern relates to human vulnerabilities, such as complacency/inattention, distraction, low attentional resource, low arousal, disorientation, tiredness etc, and stressors (i.e., workload, etc.). These concerns arise from some relatively recent accidents and incidents.

Safety experts emphasize that it can be difficult for humans to effectively monitor for errors and deviations on a continuous basis when errors and deviations rarely occur, particularly in a highly automated environment. This holds true over the range of workload conditions experienced by the flight crew members. Monitoring during high-workload periods is critical because these periods present situations in rapid flux and because high workload increases vulnerability to error. However, studies show that poor monitoring performance can be present during low-workload periods as well. Lapses in monitoring performance during lower-workload periods are often associated with boredom, complacency, or both.

Potential challenges and barriers to effective monitoring include:

  • Time Pressure – Time pressure can exacerbate high workload and increase errors. It can also lead to rushing and “looking without seeing."
  • Lack of Feedback – When monitoring lapses occur, pilots are often unaware that monitoring performance has degraded.
  • Design of SOPs – Procedures may fail to explicitly address monitoring tasks.
  • Automation – Pilots’ inadequate mental model of autoflight system modes. Pilots may not have a complete or accurate understanding of all functions and behaviours of the autoflight system. Some aspects of automated systems for flightpath management are not well matched to human information processing characteristics.
  • Training – Training may overlook the importance of monitoring and how to do it effectively. Lack of emphasis on monitoring may occur in training and evaluation.

Solutions

While different types and levels of pilot training may involve pilots with differing levels of competence, the training of flight path monitoring should include uniform objectives and standards. Therefore, because the same monitoring concepts apply to all pilots, course content should not differentiate between different types of training courses. A graduated approach should be taken in developing an integrated pilot monitoring training program. It should start with solid grounding in theoretical knowledge, followed by instructor-led case studies. This should include videos and finally line-oriented flight training (LOFT), progressively building on each layer of content:

  • Knowledge – Without proper knowledge of systems and automation, the flight crew will not be able to understand nor predict the aircraft’s behaviour.
  • Skill – Without the necessary skills to operate the aircraft effectively, a flight crew will be overwhelmed by the flight path monitoring tasks.
  • Discipline – Discipline is a foundation for monitoring. Adherence to division of duties is essential for managing workload.
  • Attitude – Developing the right attitude often is the most important aspect of a training program.

Monitoring requires motivation and discipline and must be a continuous effort. The primary aim for flight crew members should be to effectively monitor the flight path, but first, flight crews must be well-trained in flying skills, discipline and behaviours . Without these, effective monitoring may not be possible.

Accidents & Incidents

On 20 December 2019, an Airbus A318 making a tailwind ILS approach to Toulon-Hyères with the autopilot engaged and expecting to intercept the glideslope from above had not done so when reaching the pre-selected altitude and after levelling off, it then rapidly entered a steep climb as it captured the glideslope false upper lobe and the automated stall protection system was activated. Not fully following  the recovery procedure caused a second stall protection activation before a sustained recovery was achieved. The Investigation noted Captain's  relative inexperience in that rank and a First Officer's inexperience on type.

On 7 September 2019, the crew of a Boeing 737-800 completed a circling approach to runway 18R by making their final approach to and a landing on runway 18L contrary to their clearance. The Investigation found that during the turn onto final approach, the Captain flying the approach had not appropriately balanced aircraft control by reference to flight instruments with the essential visual reference despite familiarity with both the aircraft and the procedure involved.It was concluded that the monitoring of runway alignment provided by the relatively low experienced first officer had been inadequate and was considered indicative or insufficient CRM between the two pilots.

On 29 February 2020, an Airbus A320 inbound to Delhi lost separation against an outbound A320 from Delhi on a reciprocal track and the conflict was resolved by TCAS RA activation. The Investigation found that the inbound aircraft had correctly read back its descent clearance but then set a different selected altitude. Air Traffic Control had not reacted to the annunciated conflict alert and was unable to resolve it when the corresponding warning followed and it was noted that convective weather meant most aircraft were requesting deviations from their standard routes which was leading to abnormally complex workload.

On 18 September 2018, an Airbus A320 crewed by a Training Captain and a trainee Second Officer departing Sharjah was cleared for an intersection takeoff on runway 30 but turned onto the 12 direction and commenced takeoff with less than 1000 metres of runway ahead. On eventually recognising the error the Training Captain took control, set maximum thrust and the aircraft became airborne beyond the end of the runway and completed its international flight. The Investigation attributed the event to the pilots’ total absence of situational awareness noting that after issuing takeoff clearance, the controller did not monitor the aircraft.

On 16 May 2013, a DHC6-300 on a domestic passenger flight made a tailwind touchdown at excessive speed in the opposite direction of the of 740 metre-long runway to the notified direction in use and, after departing the runway to one side during deceleration, re-entered the runway and attempted to take off. This failed and the aircraft breached the perimeter fence and fell into a river. The Investigation identified inappropriate actions of the aircraft commander in respect of both the initial landing and his response to the subsequent runway excursion and also cited the absence of effective CRM.

On 16 May 2013, a DHC6-300 on a domestic passenger flight made a tailwind touchdown at excessive speed in the opposite direction of the of 740 metre-long runway to the notified direction in use and, after departing the runway to one side during deceleration, re-entered the runway and attempted to take off. This failed and the aircraft breached the perimeter fence and fell into a river. The Investigation identified inappropriate actions of the aircraft commander in respect of both the initial landing and his response to the subsequent runway excursion and also cited the absence of effective CRM.

On 3 November 2019, a Boeing 787-8 descending towards Barcelona experienced an unanticipated airspeed increase and the unduly abrupt manual pitch response which resulted in a large and rapid oscillation in vertical acceleration during an otherwise smooth descent resulted in two serious injuries, one to a passenger and the other to one of the cabin crew. It appeared that the cause of the airspeed increase was an unexplained vertical mode reversion from VNAV SPD to VNAV PTH about 20 seconds prior to the upset caused by the response to it. 

On 25 November 2019, an Airbus A330-300 being used for type conversion line training was involved in a landing tailstrike at Yangon during the trainee senior Captain’s first line training flight in benign daylight conditions. The Investigation noted that the optional tailstrike prevention system was not installed on the aircraft involved and found that the operator’s standard calls for excessive pitch during landing had not been made, that the trainee had misinterpreted the Training Captain’s pitch attitude guidance during the landing and that the Training Captain was only used to having to take over control when working with junior pilots.

On 22 August 2019, a Boeing 737-800 positioning visually from downwind after accepting clearance to make an approach to and landing on runway 03L at Hyakuri instead lined up on temporarily closed runway 03R and did not commence a go around until around 100 feet agl after seeing a vehicle on the runway and the painted runway threshold identification. The Investigation concluded that the event occured due to the captain not thoroughly performing the visual recognition of runway, and the FO not adequately monitoring the flight status of the aircraft thus failing to correct the runway misidentification made by the Captain.

On 2 February 2013, an ATR 72-500 bounced repeatedly when making a night landing at Rome Fiumicino which, in the presence of dual control inputs causing a pitch disconnect, resulted in complete detachment of the landing gear and a veer off before stopping. The accident was attributed to uncharacteristic mishandling by the type experienced Captain in the presence of ineffective crew resource management because of an extremely steep authority gradient resulting from a very significant difference in flight time on the aircraft type (9607 hours / 14 hours). The Investigation attributed an unacceptable delay in the rescue services’ response to managerial incompetence.

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