How many fire trucks does a certain airport have? This is a question almost no airline passenger asks. But certainly all pilots should be aware of what the RFFS at the departure, destination and alternative aerodromes are comprised of.
The minimum RFFS’ capabilities and equipment is (and I would say has to be) regulated: depending on what the user aircrafts at the airport are, the number of firefighting vehicles and the number and quantities of fire extinguishing agents will vary.
As mentioned in the “What are the RFFS exactly?” article, the Federal Aviation Administration and ICAO have different ways of doing equivalent tasks: determining the rescue and fire fighting categories is one of those things.
Prior to going any deeper into the matter, it must be noted that an airport’s ARFF/RFFS category can change over time, as air carriers’ appear and disappear, their fleets change, etc.
The ICAO way
In ICAO’s Airport Service Manual Part 1 it is said that “The level of protection to be provided at an airport should be based on the dimensions of the aeroplanes”. The first dimension to take into consideration is the aircraft length and the second is the fuselage width, the reason for this being that a short but very wide(fuselage-wise) airplane might carry more fuel and passengers than a short and not-so-wide aircraft. The category-defining specification is, in the end, the fuselage width.
ICAO defines ten airport categories and specifies the minimum amount of water, dry chemical powders (or “other complementary agents having equivalent fire fighting capability”) and discharge rates of the crash tenders for each case. Although it is recommended to have principal and complementary agents, it is implicitly demanded to have both of them at the airport (in or on the trucks). It is also implicitly demanded a turret on the trucks, as no human can hold on to a nozzle+hose delivering such great high pressure discharge rates.
Prior to 2005 the number of aircraft movements was considered and the airport’s RFFS category could be downgraded to two categories below if there were not many movements of the largest aircraft during the three busiest consecutive months. Nowadays “during anticipated periods of reduced activity, the level of protection available shall be no less than that needed for the highest category of aeroplane planned to use the aerodrome during that time, irrespective of the number of movements”. After all, it would be possible to downgrade the category just one level.
If the airport and its approach/departure areas are over the water, swamps or other difficult environments, more vehicles, suitable to those surroundings, should be available. However, this does not eliminate the need for having a minimum number of airport firefighting vehicles or alter in any way the aerodrome’s category.
The FAA way
The FAA calculates the ARFF index (five possible indexes) by considering the length of aircraft and the average daily departures of aircraft: “If there are five or more average daily departures of aircraft in a single index group serving that airport, the longest aircraft with an average of five or more daily departures determines the Index required for the airport. When there are fewer than five average daily departures of the longest air carrier aircraft serving the airport, the Index required will be the next lower Index group than the Index group prescribed for the longest aircraft”. In other words, it says that at least five departures a day are needed for the biggest aircraft to affect the index category.
In Part 139.317 is detailed how to organize the vehicles and their contents, not leaving room for doubt over those issues. Plus, it is explained when a turret is to be installed.
- Index A airports (Aicraft length < 90 ft (≈27,4m)) need at least one vehicle.
- Index B airports (Aircraft length 90 ft ≤ L < 126 ft (≈38,4m)) need one to two vehicles, depending on the equipment layout.
- Index C airports ((Aircraft length 126 ft ≤ L < 159 ft (≈48,6 m)) need two to three vehicles, depending on the equipment layout.
- Index D airports ((Aircraft length 159 ft ≤ L < 200 ft (≈61 m)) need three vehicles.
- Index E airports ((Aircraft length ≥200 ft (≈61 m)) need three vehicles.
Generally, the amounts of water, complementary agents and the discharge rate required by the FAA are lower than what ICAO demands. Nevertheless, these numbers are minimum requisites and almost every airport operates well above these. For example, Sabadell Airport (ICAO: LELL) is an ICAO Category 3 airport with double the vehicles required, or Frankfurt Airport (ICAO: EDDF IATA: FRA), an ICAO Category 10 airport which has 9 vehicles only for first-emergency and firefighting response to the aircraft, plus dozens of other vehicles for other purposes. However, both methods are in fact very similar as can be seen in this approximate comparison chart:
One other aspect which has to be mentioned is that FAA regulates ARFF in airports with commercial traffic of aircraft and passengers. On the other hand, ICAO’s regulations “apply” to all aerodromes and airports, including small general aviation aerodromes. That is why ICAO has 5 categories to the FAA’s A index, so that every airport operator can adjust to what is needed and still meet regulations without incurring in higher costs than necessary.
An airport‘s ARFF/RFFS category must be published in the AIP.
If a substantially bigger than the A380 aircraft goes into production someday, the categories will be updated and an eleventh category may appear.