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Flight Crew Workload in Preparation for the Execution of an Approach
|Category:||Toolkit for ATC - Stabilised Approach|
The key flight crew activity prior to any approach is a briefing given by Pilot Flying (PF) to Pilot Monitoring (PM). Such a briefing can take a very wide range of forms depending on circumstances. However, it will usually be interactive to some degree so that both pilots can be confident after completion that they share the same awareness during the approach.
For a normal flight, the briefing for the approach is the only significant briefing carried out when the aircraft is in flight.
The nature of any particular briefing - and therefore the time it takes - will be influenced by a number of factors:
- The extent of relevant Standard Operating Procedures detailed in the Operations Manual.
- The extent to which aspects of the approach were covered during flight preparation in the crew briefing room at duty commencement.
- Long haul or short haul sector.
- The type and general experience of the crew members involved.
- Presence of extra crew on a long haul flight.
- The personality of the aircraft commander.
- The familiarity of each crew member with the destination and its procedures.
- The prospect of adverse weather or otherwise which could affect approach, go around or runway conditions.
- Whether an instrument approach is to be flown with radar vector.
- Any abnormally severe consequences of runway excursion.
- Whether the autopilot is to be used and to what disconnect height.
- The inherent complexity of the approach procedure – e.g. a circling approach to a runway other than the one to which the initial instrument approach is made.
- Special airworthiness circumstances which will increase crew workload at already busy stages of the approach. This will not be known to ATC because they do not invite the special or priority treatment which would require a ‘PAN’ call. Either conditions arising from MEL items or conditions which have arisen en route may be involved. Examples are manual operation of air conditioning and pressurisation and an inoperative APU.
Depending on the context, a brief may cover an extensive range of items. And for each one, it may do so with a range of levels of detail. This, subject to Operations Manual requirements, allows the crew members, guided by the aircraft commander, to exercise their professional judgement in respect of what a particular briefing should include.
Items to be covered in an approach brief may include those in the list below.
- Approach procedure and runway in use expected based on current ATIS broadcast and available forecasts by reference to relevant Flight Guide Plates; full procedure brief; ILS glideslope validation method and final approach track check altitudes; use of radio altimeter unless a prescribed SOP applies; review of approach ban (this normally includes visibility/RVR to be below the appropriate minimum) if applicable. *
- Setting of navigation aids, use of Flight Management System (FMS), Autopilot (AP), autothrottle ( A/T). *
- Altitude and position-based calls to be made by PM unless prescribed SOP applies to all.
- Applicable approach minima - low time in command or minor airworthiness deficiencies may require increased minima. *
- Options following any initial missed approach. *
- Missed approach procedure and stop altitude for likely runway plus brief consideration of differences for parallel runways if change of runway possible. *
- The immediate sequence of crew actions required to initiate a go around following a PF call of one. **
- Adverse weather challenges - risk or actual presence of wind shear, low visibility, high wind velocity - effect of wind gusts on applicable landing limitations; potential for low level mechanical turbulence from aerodrome structures or local topography.
- Relevant Safety Altitudes, general disposition of terrain, published radar vectoring minima. *
- Fuel status implications of any anticipated or notified delay to an approach; if an EAT has been issued then maybe slow down if the position in landing sequences is reliably assured.
- The after-landing turn off and any potential taxi-in hazards including promulgated or otherwise known hotspots.
- Aircraft landing performance - a check that the intended / assigned runway will be suitable for landing with the aircraft at the expected landing weight in the prevailing environmental conditions - includes climb performance in the event of a go around. *
- Reminder of the need for the PM to make alert calls for any instance of excessive bank, pitch or abnormal speed trend as per SOP requirements if given or at the discretion of the commander if not.
Most will include at least some remarks in respect of the single * or double ** starred items which are the ones most often included in Operations Manual minimums for the brief.
Double stared items ** are often omitted after the first approach briefing of several in a short haul flight sequence within a single crew duty period.
On long haul flights, there is both more time to conduct the approach briefing and a need to ensure its relevance and possibly involve heavy crew members so that, in contrast to a short haul flight, the duty-commencement briefing is unlikely to go into much detail in respect of the eventual approach.
For a short haul flight, however, matters which should have been covered during a duty-commencement or pre flight ground briefing so as to reduce the time spent briefing in flight include:
- An assessment of the likelihood of adverse weather at the destination or on the approach at the expected time of arrival.
- All highlighted / trained special aspects of a Cat B or Cat C destination or designated alternate.
- Any variation between commercial and RPL / FPL listed alternates
Matters which could usefully have been covered in the case of a short haul flight include:
- The potential effect of any increased minima for the aircraft commander or co pilot.
- Any obviously complex landing runway clearance and taxi in issues including likely runway crossings, restricted taxiway use e.g. gross weight or wingspan-restricted, whether aircraft ground routing control is active or passive and likely gate location.
An approach briefing will normally be conducted with the autopilot engaged. The effective conduct of a briefing requires that it occurs without (much) interruption and at a time when the crew workload is light. This effectively means that it should be completed towards the end of the cruise. Many Operations Manuals specify exactly this as SOP and also include a check to confirm its completion in the ‘Descent’ Check List, which is completed before descent is commenced.
Any approach re-briefing which might have to be conducted later would be at risk of being interrupted by either or both of ATC communications and aircraft management priorities. Interruption will seriously diminish the effectiveness of any in-flight briefing because it will cause it to become disjointed and possibly rushed as a response to the high workload environment in which it is being conducted.
Subsequent Revision of an Approach Brief
For a number of reasons, it may be necessary to make minor or major revisions to the approach brief initially given. This may need only a minute or two but rather longer if there has been a complete change of approach and landing runway. This will most often happen due to:
- Sudden change of wind direction and / or speed relative to the available runways.
- A revised ATC operational plan involving either an instruction or an (optional) opportunity - unexpected runway blockage might require this.
Other ATC-originated changes might include offers of a reduced track mileage and the opportunity to carry out a visual approach. Any significant change is normally accepted (or in some circumstances requested ) when there is clearly sufficient time to touchdown remaining for an adequate crew re-brief and revisions to FMS and other flight management settings to take place. Crew workload issues in both respects may mitigate against the acceptance of changes or lead to a crew decision to initiate a go around. Most but not all crews will be able to recognise the tactical risk assessment boundary between ‘can do’ and a decision to go around.
A flight crew approach brief can take many forms subject to any prescription which may be detailed in the operator SOPs but it always has a single common objective - to preview what will or might well happen during an imminent approach and landing.
The content and the time it takes to complete can be expected to vary according to the extent of the perceived relative difficulty in flying a particular approach in the prevailing circumstances. There is no such thing as a typical briefing but the time to complete the majority of them might be within the range 2 - 6 minutes and it can be excepted to be conducted 10 minutes before reaching the top-of descent point.
As with other professionals, pilots do not always perform with the same effectiveness from day to day or compared to their colleagues, so ATC must anticipate no more than broadly similar ‘standards’ of skill. However well prepared a crew is, it is almost guaranteed that any significant changes to their approach expectation (e.g. approach type, especially from precision to non-precision type or runway change) after the planned initial brief has been completed will lead to increased workload and the possibility of a poorly flown approach or a go around and the consequent delay.
- Stabilised Approach
- European Action Plan for the Prevention of Runway Excursions (EAPPRE) Edition 1.0, January 2013.
- DGAC (France) Publications on Non-Stabilised Approaches
- CFIT Precursors and Defences
- Continuous Descent Final Approach
- Non-stabilised Approach After ATC-Requested Runway Change (OGHFA SE)
- Runway Overrun After Unstabilised Approach (OGHFA SE)
- Monitoring Skills (OGHFA BN)
- Adherence to SOPs (OGHFA BN)
- CANSO Report - Unstable Approaches: ATC Considerations
- Best Practice in Pilot Monitoring - Manage Workload: UK CAA video.