M ANAGEMENT S YSTEM
1.5 Approach Control (APP) Operations
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Once the engines are running and all after-start checklists are completed, a taxi clearance is obtained from the ground con-troller. In large airports, taxiing may take several minutes while proceeding though various taxiways and intersections may be a complex task that requires constant monitoring and coordination with ground controller. Both crew members are monitoring the taxi route and try to avoid the “heads down” syndrome in the cockpit.
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The selection of the approach sequence is a difficult task since the selection is made from a large number of alternative sequences (e.g., 5 arrivals generate 5! or 120 sequences). The flight crews are guided to establish the ILS at the appropriate altitude, speed, and angle with the advice of the APP controllers who later transfer control to the TWR unit.
The role of the APP unit is to provide separation instructions and maintain a safe and expeditious traffic flow. The normal separation minima are 1000 ft vertically and between 2.5 to 5 Nm horizontally.
In this way, a protected airspace is created around each aircraft and traffic should be regulated to prevent overlaps between the protected spaces (Figure 1.9).
1.5.1 Approach Controller Duties
The description of the duties of APP controllers is provided in the training and operational manuals of the APP units and include com-mon and specialized duties for the EC and CC positions.
Entry point alpha
Entry point bravo
ILS final approach course
Figure 1.8 A schematic of two arriving flows merged for landing in a runway.
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The generic duties that are common to the EC and CC positions are as follows:
• Adjust the relevant displays so that the control functions can be performed properly; notify the watch supervisor for any technical failures
• Analyze, plan, and control the flow of traffic by using infor-mation from the radar and other systems
• Detect potential conflicts between aircraft
• Provide and maintain separation between aircraft between aircraft and airspace boundaries and between aircraft and terrain
• Manage concurrent tasks
• Monitor and ensure that flight data displays and flight strips are maintained up-to-date
• Prioritize and delegate tasks when appropriate
• Communicate with aircraft and colleagues in a clear and pre-cise manner
• Ensure that coordination is in accordance with prescribed procedures
• Manage air-ground and ground-ground communication failures
• Assist and give priorities to aircraft in emergency.
The specific duties for the EC position are:
• Maintain a continuous listening watch on the unit frequen-cies and carry out RTF communications with the aircraft
• Take all necessary actions within the area of responsibility to comply with the coordination plan established by the CC
1.5 Nm 500 ft 1.5 Nm
500 ft
Figure 1.9 A protected airspace created in the case of 3 Nm horizontal and 1000 ft vertical separation.
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• Liaise with the CC position when planned exit levels or other arrangements cannot be achieved
• Ensure that the CC position is warned about traffic situations that overload the area of responsibility of the unit
• Ensure that the CC position is informed of any unusual situ-ations accruing in the unit
The specific duties for the CC position are as follows:
• Plan and accept aircraft into the AoR in accordance with prescribed procedures
• Plan exit conditions in accordance to the planning standards or as agreed with the accepting unit
• Ensure that the coordination with the adjacent units is effected prior to the transfer of aircraft
• Coordinate with EC position to accept aircraft that does not comply with navigation or communication requirements
• Transfer radar identity of aircraft to the EC position
• Ensure that the EC position is aware of any coordinated air-craft climb or descent made with adjacent units
• Inform the watch supervisor of any unusual situations in their area of responsibilit
1.5.2 Pilot Duties during Take-off, Climb, Descent, and Approach for Landing Most flight procedures for takeoff, climb, descent, and approach for landing are carried out by the flight crews while traffic is regu-lated by the approach control unit. It makes sense then to provide a short description of the duties of flight crews and the challenges they face.
The takeoff procedure begins when the aircraft enters the run-way, once the crew completes the before takeoff checklist. When lined up on the runway and cleared for takeoff, the pilot flying (PF) starts to advance the thrust levers once the engines have spooled up.
During the takeoff roll, the pilots cannot reject the takeoff unless spe-cific conditions prevail (e.g., runway incursions, low level windshear warning, engine failure, crew incapacitation).
During climb, the flight crew positions the aircraft to a safe height away from terrain and obstacles. For this reason, the engine thrust is set to a high “takeoff power” setting and the aircraft attitude is pitched
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up to maintain a specific speed. Once the safe height is reached, the engine thrust can be reduced to a more efficient setting. In order to provide minimum noise disturbance to the area surrounding the air-port, regulatory procedures require the aircraft to fly specific profiles (i.e., noise abatement procedures).
The descending process starts with the determination of the top of descent (TOD) point in order to achieve a continuous idle power descent from the cruising level until a certain point on the final approach. In many cases, the calculation of the TOD point is per-formed by the FMS on the basis of several factors (e.g., tail/head winds and the descent speed given by the cost index) and accounts for the distance required to effectively manage a final approach speed.
During final approach, the workload of the flight crew peaks as multi-ple tasks may be required at the same time. At this high workload phase, the crew should also arrange the landing configuration of the aircraft.
This is a safety-critical task since the aircraft flies at a low level, with minimal speed, close to terrain, and with little margin for maneuvering.
If a nonprecision approach is flown, the workload of the flight crew gets higher because the pilot not flying (PN) becomes very busy since, at each mile, s/he must state the aircraft’s position relative to the required vertical profile and predict the altitude of the flight at the next mile checkpoint. In addition, the automatic aircraft systems are not capable of “locking onto” a nonprecision path in final approach.
This is different from the case of an ILS approach where the autopi-lot can “lock onto” the localizer and glide-slope signals allowing the flight crew to monitor the flight path. The flight crew is obliged to fly a “stabilized approach” avoiding any problems due to deviations from the correct flight parameters. In the stabilized approach, the SOPs ensure that the aircraft is on the correct flight path, the flight param-eters are within limits and other controls are put on specific positions (e.g., the engines are set at an appropriate power setting, the gear is down, and the flaps are set for landing).
To accomplish a successful landing, the aircraft must be “flared”
prior to its touchdown where the engines are commanded to idle power.
Sometimes, upon touchdown, the aircraft may not be in a “roll-out”
mode which requires the autopilot to be disconnected so that the pilot flying can control the aircraft and maintain the runway center line during the landing roll. After landing, the flight crew must accomplish many actions, such as change radio frequency, receive taxi clearance,
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and check the taxi route on the airport charts. After vacating the runway, the aircraft may continue the taxi to an assigned stand.
In this sensitive flight phase, emphasis is given to the removal of nonessential verbal communication between crew members that may distract from essential tasks. In general, most operators employ “ster-ile cockpit” procedures that call for a “verbal s“ster-ilence” below a certain level during climb or descent.