Chocks ON to Chocks OFF

Published by: Saurabh sharma on 4th May 2009 | View all blogs by Saurabh sharma

Before Flight

  • The crew checks the departure, destination, alternate and diversion airports weather, orders sufficient fuel, taking into account all the possible contingencies. Normally a standard fuel that conform to the minimum ICAO (International Civil Aviation Organization) requirements are carried. For example, for a 12 hours flight, about 100 tons of fuel would be carried. This would include the trip, diversion, contingency, holding reserve and instrument approach fuel.
  • Checks all relevant documents are on board the aircraft
  • Checks latest notices to airmen as regards to safety of airspaces, example, whether there are any volcanic activities that may affect the routing, or airfield restrictions such as closure of some taxiways due to some constructions, etc.

    At the Aircraft

    • The co-pilot usually carry out a visual inspection of the aircraft, amongst others, to ensure that there is no fuel leaking or dripping from unseen pipelines under the aircraft body or undercarriage areas, tires not worn out, engine turbine blades are in good condition, etc.  He checks everything and anything so as to satisfy himself that the external condition of the aircraft does not affect its safety to proceed on the flight.
     

         Starting the Engines
    • Approval is required from the Control Tower to start the engines. The Control Tower will then advise when would be the proper time to start the engines so as not to waste unnecessary fuel. Delays can be as long as 30 to 45 minutes, especially in obtaining route clearances.
    • Normally the right engine is started first but on the Boeing 777, both the engines are started together due to the fact that the aircraft has a very powerful auxiliary power unit

      Push Back and Taxi Out

      • After all the doors are closed, a motorized vehicle called the tow truck is used to push the aircraft back from its gate. The aircraft then moves under its own power along the taxiways. Push back occurs only when the pilot has clearance to do so from the Control Tower.
       

      Take Off

      • Delays can also arise if there are too many aircraft taking off or landing from the same runway.
      • During take off, the pilot releases the brakes and applies power to accelerate down the runway, steering the aircraft with foot pedal or nose wheel steering on the runway center line.
      • This is the most critical stage of the flight as the engines are at maximum power (about 90,300 lbs of thrust each) to lift the aircraft at a maximum weight of about 287 tons off the 2 miles (3.6 km) long runway.
      • When the airspeed reaches the rotation velocity, the pilot gently pull the control column back to lift the plane off the ground at around 150 knots (170 mph/270kph)
      • The wheels are then retracted into a cavity in the belly of the aircraft after it is airborne. If you are sitting near the nose of the aircraft, it may be a bit noisy due to the retraction of the landing gears and the slight thumping sound when they are locked up.
       
       

      Climb

      • The aircraft climbs at about 320 knots (370 mph/570 kph), at an average rate of 1500 feet per minute to its cruising altitude.
      • You should reach your cruising altitude of about 35,000 feet (about 7 miles) in about 25 to 30 minutes depending on the weight of the aircraft.
      • The weather radar is normally switched on when there are bad weather or clouds ahead so that the pilot can avoid any turbulence associated with them.
      • The TCAS (Traffic Alert and Collision Avoiding System) as explained in the earlier FAQ is selected on to detect any unknown aircraft that might accidentally fly into the flight path.

        Cruise

        • During cruise, the weight of the aircraft and the lifting force generated by the wings are exactly equal.
        • There is no standard altitude for cruising but it is generally between 30,000 to 43,000 feet. However, it can vary considerably depending on the length, the direction, (Easterly or Westerly), air turbulence or other aircraft on the same route.
        • The aircraft cruises around 480 knots (550 mph/880 kph) but this can vary depending on the headwinds, tailwinds or other factors.
        • During flight, pilots normally follow designated Airways, or highways in the sky, that are marked on flight maps. On the Boeing 777, the GPS or Global Positioning System, as explained in the FAQ helps the pilot to navigate from one point to the other.
        • The aircraft is constantly in contact with the ground on the radios. The pilots must report their positions at designated points on the Airways if they are not under the control of the ground radar stations.
        • In airspaces where there are radar control, aircraft are constantly being monitored through the transponder system, a device which will enable the ground radar stations to observe its speed, height and location.
        • The aircraft is normally under the control of the auto pilot. At this point, the role of the pilot is to manage the systems, keeping an eye on all the engines instruments to ensure that they are within limits, make position reports and to take over the aircraft immediately should any of the control systems operated by the auto pilots fail.
        • On long distance flight, the Boeing 777 will issue a warning when no routine actions have been performed to check the systems within the last 15 minutes. This is one way to monitor that the Captain and co-pilot are still awake!
        • Somewhere along the halfway mark on a long haul flight, the relief crew will take over the flight. For example, on a flight of 12 hours duration, the flight will be shared equally in terms of flying duty, that is, 6 hours each. The two sets of crew are nominated as 'A' or 'B' Team. Normally, the 'A' Team consisting of a Captain and co-pilot will carry out the initial take off and the final landing, flying the first five hours and the last one hour.
        • The pilots also monitor the weather of the en-route alternate airports at this point and check their suitability for any unforeseen emergency diversion should the need arise.
        • Whenever the crew are operating over high terrain, especially those above 10,000 feet, they often mentally prepare themselves for any emergency depressurization. A loss of pressurization around this region will be critical as the aircraft must be descended to around 10,000 feet to avoid the problem of hypoxia, or the lack of oxygen. They must be aware of any escape routes during the descent in order to avoid high ground as they undertake the diversion to a suitable airport in these mountainous terrain.
        • Aircraft sometimes encounter clear air turbulence while cruising in the vicinity of jet streams. Therefore, it is advisable for passengers to have their seat belts on whenever they are seated even if the seat belt signs are off. In normal turbulence associated with clouds or thunderstorm, sufficient warning will normally be given by the pilots as they are often visible in the weather radar screen inside the cockpit.
         

        Before Descent

        • The pilot checks the destination and alternate weather. If the destination weather is unfavorable, he might consider a diversion or plans for an automatic landing provided the conditions are conducive. A briefing, reviewing all the procedures would be carried out between the Captain and the co-pilot, such as actions to be taken in event of system malfunctions during the automatic landing or other details that may affect a safe touchdown. Even though the aircraft lands by itself during a normal automatic landing, the pilot must take over the landing should 2 of its 3 auto pilots fail.

          Descent

          • The pilot will commence descend at a point determined by the aircraft's computer but clearance must first be obtained from the control tower.
          • The control tower then sequence the aircraft to land, carefully separating it from all other aircraft headed for, or leaving the same airport.
          • The aircraft descent initially at around 300 knots (350 mph/540 kph) and gradually reduces to about 130 knots (150 mph/230 kph) at touch down. The landing gears are lowered on the final approach and they are slightly noisy until fully down and locked.
           

          Landing

          • The landing phase is also the other most critical phase of the flight besides the take off.
          • The control tower normally directs the aircraft to land into wind to reduce the ground speed, but airfield design and weather conditions are never always in favor to allow aircraft to land exactly into winds at all times.
          • As a result, in a crosswind landing, you will see the aircraft nose pointing away from the runway. Not to worry, the pilot or the autopilot will eventually maneuver the aircraft to touch down with a slight wing down, and straight along the centerline of the runway.
          • Once the aircraft has landed, the flight crew start to slows down with several quick actions, pulling back on the throttles, raising another set of controls known as the 'spoilers' to disrupt airflow over the wings, reversing the thrust of the engines and at the same time, applying the brakes. In this situation, the pilot is executing a manual landing. On an auto landing, all the landing actions are automatic except for selecting the reverse thrust. The Captain then disconnect the auto brakes otherwise the aircraft will come to a complete stop on the runway. He will take over manually on the brakes so that he does not block the runway and then taxi swiftly back to the parking bay.
          • A point to note, smooth landing is not necessary the best landing on a runway that is wet after a rain. This is because a soft landing may not activate the spoilers, a device to kill the lift on the wings in order to give the aircraft a better braking action. On a wet runway, you want to touch down and brake as soon as possible, or else you run out of runway!

            After Landing

            • Delay in getting a parking bay is quite common in busy airports or if the aircraft arrives too early due to a strong tail wind.
            • When an aircraft stops with the seat belt signs on, it does not mean that the aircraft has reached a parking bay. Passengers are advised to be seated with their seat belts on until told to unfasten them.
            • In an airfield the ground wind was so strong that they had to wait for as long as an hour for the wind to subside because the limitations of the aerobridge doors were exceeded. In order to open the doors of the aerobridge, the wind must be less than 55 knots (63 mph/100 kph)
            • Once all the passengers have disembarked, the aircraft is handed back to the ground engineers who would carry out all the necessary maintenance actions. He would then refuel the aircraft for the next service. The Captain and its crew would then be transported to the Hotel for a good rest before the next flight home.
             
           
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