Airlines and pilots are required to comply with the noise abatement procedures in effect at Montréal–Trudeau in order to reduce noise disturbances generated by air traffic.
Takeoff and landing procedures
Planes must take off and land into the wind. At Montréal–Trudeau, the prevailing winds are southwesterly, so aircraft usually land and take off in the direction of Lake St. Louis (southwest).
In addition to the exceptional procedures during restricted operating hours (see below), pilots are required to follow these procedures at all times:
After takeoff, jets must climb in line with the runway to a minimum altitude of 915 metres (3,000 feet) before starting a turn. Turboprop and piston (propeller) aircraft initiate a turn as soon as possible following take off to clear the runway's flight path.
While landing, jet pilots must be aligned with the runway’s centre line on final approach, respecting an angle of descent of 3 degrees; pilots must also adjust the thrust/drag speed on descent, to the extent that safety permits, in order to achieve a minimum noise level.
Operating restrictions during certain hours
Montréal–Trudeau Airport is open 24 hours a day to propeller planes and jets weighing less than 45,000 kilograms. As for jets weighing more than 45,000 kilograms, normal hours are between 7 a.m. and midnight for take offs and between 7 a.m. and 1 a.m. for landings.
Aéroports de Montréal (ADM) does, however, have the right and the authority to make exceptions to these restrictions for medical emergencies, delays beyond a carrier’s control and adverse weather conditions.
A strict internal policy applies in such cases. In particular, exceptions granted for scheduled flights represent a very small percentage of total traffic and they must be supported by strong operational reasons; furthermore, exceptions are contingent upon adherence to the noise abatement measures in force.
ADM grants exceptions to certain aircraft for departures before 7 a.m. and for late arrivals. However, only the quietest aircraft are eligible.
Restrictions on engine testing
Engine testing at high RPMs for inspection or maintenance purposes is forbidden between 11 p.m. and 7 a.m. Special permission may be granted in some cases, such as when aircraft must be on standby to respond to emergencies in isolated regions. Engine testing at high RPMs is performed in areas chosen in order to minimize noise disturbances for nearby residents.
Assignment of priority runways for night flights
Night-time runway use is determined by a priority runway assignment system outlined in the Canada Air Pilot (CAP).
This assignment is dependent on wind direction:
Southwesterly/westerly winds (70% of the time): South runway (24L) for takeoffs and north runway (24R) for landings
Easterly/northeasterly winds (30% of the time): North runway (06L) or south runway (06R) for takeoffs and landings