Cold Conditions – Snow and Ice

Inclement weather such as heavy snow and icing conditions require specific activity in relation to airport performance and aircraft preparation. Airports located in prone areas are typically well equipped with snow ploughs and other heavy machinery designed to rapidly remove contamination from movement areas. On occasions though, conditions such as heavy snow create significant disruption as the capability of equipment is exceeded. Other than complete airport closures, most disruptive during these events is the extent of delays due to the need for de-icing aircraft. This is a process either performed at a number of de-icing stations (most often de-icing pads) around the airport, or carried out with mobile equipment at the gate. However, there are only a certain number of deicing pads and limited equipment and staff. There is also a limited time that the spray or other treatment is effective, so de-icing is required as close to the expected departure time as possible. As a result, demand is usually high at busy times and delays are inevitable as the queue of aircraft needing the service grows.

IOC response

The IOC generally has a number of considerations to weigh up in terms of departing traffic:

• a) The duration, extent and severity of the storm.
• b) The level of traffic on the ground building up and requiring de-icing treatment.
• c) The capacity and resources of the various de-icing systems in place (and hence calculated waiting time).
• d) If the storm is particularly severe, the IOC will seek information from the Station Manager or Port Coordinator as to the capability of the infrastructure between city and airport so as to enable customer (and crew) transport to and from the terminal precinct.

The options include the following:

• a) If de-icing facilities are in high demand with imminent disruption to several services, IOCs may select specific operations to be prioritised with others either delayed or cancelled in order to protect the greater network.
• b) If a snowstorm is particularly severe and expected to be long-lasting, the IOC may elect to suspend all operations into that airport for a period.

Hot Conditions – High Temperature

Conditions at some airports located in deserts, some equatorial locations or regions prone to extreme weather, can result in very high temperatures. With reduced air density, aircraft take-off and climb performance may be substantially compromised, limiting the payload and/or range of the aircraft.

IOC response

To an extent, planning several days ahead of the day of operations tends to reveal operational problems such as this and steps can be taken well ahead to distribute the load onto other flights or change the routing of the flight to enable an en-route ‘technical’ stop for fuel. In some cases involving long-haul flights operating from known high-temperature airports, the Commercial department may have limited the saleable pay- load by blocking out a number of seats on the aircraft. This artificially limits the maximum weight of the aircraft and avoids offloading any payload. However, on the day of operation, temperatures can exceed forecasts such that a weight or performance problem only becomes known when the flight plan is prepared or even later, once the crew have signed on and considered all the information at hand. Then the decision to manage the problem falls to the IOC.

Tidal Movement

A quite unusual circumstance is the operation of an RPT service into an airport that uses a beach surface for taking off and landing. This can only occur, of course, at low tide when the beach is relatively dry and firm, and when general weather conditions enable the service to operate. From a scheduling perspective, the timetabled arrival and departure times must be planned in advance according to tide movements.

IOC response

For the IOC, the flights are expected to operate within the known tidal conditions. Should weather conditions or surface conditions at the airport not be conducive to operating, or should other reasons (e.g., maintenance, crewing) prevent a timely operation, the IOC will seek to delay or cancel the flight(s) until the conditions above are suitable, which may imply the same or similar time the following day. The decisions are more or less straightforward in such cases, and a lot of reliance is placed on the advice from the aircraft’s Captain, any qualified meteorological personnel, as well as the staff located at the particular airport.

Typhoon/cyclone/hurricane

The occurrence of a typhoon (cyclone or hurricane, terminology subject to the region of the world) is of major significance to an airline and is the cause of massive disruption in and around the affected ports. To give this event due attention, a worked example is provided in some detail toward the end of this chapter.