8. A) Expected approach time.

An expected approach time shall be determined for an arriving aircraft that will be subjected to a delay of 10 minutes or more or such other period as has been determined by the appropriate authority. The expected approach time shall be transmitted to the aircraft as soon as practicable and preferably not later than at the commencement of its initial descent from cruising level. A revised expected approach time shall be transmitted to the aircraft without delay whenever it differs from that previously transmitted by 5 minutes or more, or such lesser period of time as has been established by the appropriate ATS authority or agreed between the ATS units concerned.

An expected approach time shall be transmitted to the aircraft by the most expeditious means whenever it is anticipated that the aircraft will be required to hold for 30 minutes or more.

The holding point to which an expected approach time relates shall be identified together with the expected approach time whenever circumstances are such that this would not otherwise be evident to the pilot.

b) Icing. How it is possible to prevent icing?

Icing is a build-up of ice on the surfaces of aircraft which increases the weight of the plane, makes it difficult to climb and maintain altitudes and can lead to dangerous and even fatal results:

-increased weight of the plane can cause worsening of aerodynamic characteristics of the plane

- frozen contaminants cause critical control surfaces to be rough; it greatly degrades the ability of the wing to generate lift and increases drag

- movable controls may be jammed

- engines propellers may be crippled and cause unbalanced vibration (due to injection of ice)

- engine stoppage (due to icing up of carburetor, cowling and intakes)

- flame outs may take place

- accumulation of ice on internal or external windscreen can impair visibility

- sometimes landing gear extension may be affected

- antennas can vibrate so severely that can easily break

- different sensors can be covered with ice and transfer incorrect data to the cockpit

- excessive fuel consumption.

The combination of all these factors can lead to stall and even crash of the aircraft. In order to prevent icing de-icing procedure takes place on the ground. De-icing is a procedure that can be accomplished by mechanical methods (scraping, pushing); with the application of heat; by spraying the plane with liquid chemicals designed to lower the freezing point of water; or by a combination of these different techniques. Anti-icing system is used in the flight. Leading edges of the wing, windscreen, engine clawing are heated to prevent build-up of ice while flying in extremely low temperatures.

9. A) Priority on the maneuvering area.

All vehicles and pedestrians shall give way to aircraft which are landing, taxiing or taking off, except that emergency vehicles proceeding to the assistance of an aircraft in distress shall be afforded priority over all other surface movement traffic. In the latter case, all movement of surface traffic should, to the extent practicable, be halted until it is determined that the progress of the emergency vehicles will not be impeded.

When an aircraft is landing or taking off, vehicles shall not be permitted to hold closer to the runway-in-use than:

1. at a taxiway/runway intersection — at a runway-holding position; and

1. at a location other than a taxiway/runway intersection — at a distance equal to the separation distance of the runway-holding position.

At controlled aerodromes all vehicles employed on the maneuvering area shall capable of maintaining two-way radio communication with the aerodrome control tower, except when the vehicle is only occasionally used on the maneuvering area and is:

1. accompanied by a vehicle with the required communications capability, or

1. employed in accordance with a pre-arranged plan established with the aerodrome control tower.

b) Causes of communication problems.

Radio communication is considered to be failed if during 5 minutes the crew or the ATC unit doesn’t answer the repeated calls through all available radio communication channels.

Communication problems can be caused by a number of reasons:

Technical reasons

• Transmitter/receiver/failure

• Defect of headsets or microphone

• Broken wire

• Power failure ( engine shut down/APU failure

Human factor reasons

• Multiple communication

• Ambiguous wording

• Code switching

• Poor English

• Cultural differences

• Disbelief

• Overanticipation

• Personal friction/rank barrier

• Jargon/Garbled phraseology

Outside factor reasons

• Marginal weather (flying close to CB clouds, lightning strike, noise static, aircraft

electrification, severe icing)

• Terrain effect

• Long distance between the plane and ATC

• Traffic congestion