According to ICAO Annex 11, the aerodrome control tower is responsible to provide approach control service to the aircraft. This means that the aerodrome control tower may prohibit an aircraft from landing. A flight information service officer (FISO) provides advice and information and the pilot-in-command has the final decision. Therefore, a FISO cannot prohibit an aircraft from landing but can transfer this message when it is given by the aerodrome control tower.

ICAO Annex 11
3.2 Provision of air traffic control service

b) Approach control service:

1) by an aerodrome control tower or area control centre when it is necessary or desirable to combine under the responsibility of one unit the functions of the approach control service with those of the aerodrome control service or the area control service;

2) by an approach control unit when it is necessary or desirable to establish a separate unit.

Flight information service. A service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights.

Note: Flight information service does not relieve the pilot-in-command of an aircraft of any responsibilities and the pilot-in-command has to make the final decision regarding any suggested alteration of flight plan.