Arriving at the aircraft is a very busy time for both cabin and flight crew as a large number of tasks must be completed in a short period of time. This is particularly true if the aircraft is late coming in from the previous flight.
During a busy turnaround the aircraft is approached by cleaners, engineers, refuellers, dispatchers and so on.
One pilot will normally be setting up the flight deck, whilst the other pilot will be outside performing an external check of the aircraft to look for any defects, bird strike damage, etc and checking that sensors and probes are free from obstructions.
The pilot remaining on the flight deck will power up the aircraft and begin the pre-flight checks. This could mean starting the Auxiliary Power Unit (APU) (APU) and setting all controls in the desired positions, which is usually done in accordance with a checklist. All the emergency equipment is also checked, such as oxygen masks and fire extinguishers.
The flight deck will then be set up for the particular departure that is anticipated (headings, levels and frequencies). This is usually done by the Pilot Flying (PF) as it is he/she that will be managing that particular leg. A very important part is the Flight Management System (FMS) which is the aircraft’s main computer system that to a large extent controls the flight. It must be programmed for the flight; the whole flight must be entered from beginning to end and all waypoints checked. There is also other data that must be entered, such as the Cost Index.
At some point a dispatcher will enter the flight deck with a load sheet showing the final take-off weight and balance figures, which are based on the weights that the pilots provided during their pre-flight preparations. This is entered into the FMS, which in return provides all trip data e.g. fuel required, flight time, max flight level, etc Somewhere in the background passengers will be boarding the aircraft.
A very critical part is determining the take-off speeds, which can be done once the take-off weight is known. There are three speeds that are determined:
- V1: this is the point of no return. After passing this speed the aircraft is going no matter what;
- Vr: this is the speed at which the pilot must pull back on the stick/yoke and ‘rotate’ the aircraft so that it begins to fly;
- V2: this is the take-off safety speed and is the speed at which the aircraft may safely be manoeuvred with one engine inoperative.
Usually a separate book or laptop is used to find the speeds, which are crosschecked and then entered into the FMS. It is worth noting that all take-off calculations are based on an engine failure scenario. In other words, the aircraft should be able to stop on the remaining runway before V1 or safely take off after V1 should an engine fail.
The crew may decide to perform a ‘reduced thrust take-off’ which means using only the amount of take-off thrust required after taking into account several factors such as aircraft weight, runway length, runway elevation and the conditions of the day. This requires a separate calculation which is also cross-checked and the purpose of which is to increase the life of the engines.
The departure clearance is then obtained from ATC and is checked to ensure that it corresponds with the set-up of the flight deck. If there is a delay (slot time) the crew will tell ATC that they are ready, and hope for a better time. This can only be done if the aircraft is actually ready, meaning loaded with passengers and fuel, and all doors and hatches closed.
Once the departure is confirmed by the departure clearance the briefing can begin which tends to be given by PF. The briefing will be an in depth description of the departure and what to do in case of an emergency. If there is an Emergency Turn Procedure it will be covered during the briefing.
Use of Cost Index
The cost index entered into the FMS by the flight crew will have a dramatic effect on the FMS commanded climb, cruise and descent speeds. During fam flights controllers can observe such variance in speeds by asking the flight crew to demonstrate this. This can be accomplished by entering on the relevant FMS page the two extremes of the cost index value (i.e. zero and the maximum value) and then viewing the speed consequently given on the FMS ‘Climb’, ‘Cruise’ and ‘Descent’ pages.
Emergency Turn Procedure
The regulatory authorities specify the minimum climb gradients that must be achieved when flying instrument departures in order to ensure that a safe margin from terrain is maintained. For the case of an engine failure on take-off, the aircraft must still be able to achieve such gradients. However, if this cannot be achieved an alternative route must be specified in order to ensure that a safe margin from terrain is maintained. Such alternative routes are termed ‘Emergency Turn Procedures’. Should an engine failure occur on take-off or during the initial climb, the flight crew may therefore elect to fly the emergency turn procedure, and this may require a very different route to be flown compared to the cleared route e.g. the route may be different to the Standard Instrument Departure (SID).
Individual operators are responsible for determining their own emergency turn procedures and gaining such an approval from the regulatory authorities. Emergency turn procedures are therefore operator specific. Note that this may mean that the same aircraft type has differing procedures with different operators.
Emergency turn procedures are therefore available in the flight deck to enable flight crews to reference them appropriately. Controllers can therefore ask to view such details for their information during fam flights.
|Things to look out for
- How the crew handle late slot times.
- How the crew cross-checks the performance data.
- The contents of the briefing and the actions that the flight crew decide upon in case of an emergency. Does this tie up with what you would be expecting as an ATCO?
- How the flight crew set up the flight deck for an emergency turn, and how they brief for it.
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