Munich’s remote aircraft de-icing facility is 20 years old this month. Tom Allett reports.
Twenty years ago, in November 1992, Lufthansa and Munich Airport formed a joint subsidiary, Gesellschaft für Enteisen und Flugzeugschleppen am Flughafen München mbH; better know as EFM.
The new Munich airport had opened in May that year and the fledgling EFM brought together all the ground handling activities from the old Munich Airport at Riem under a single umbrella company. At the old airport some of the handling duties – such as aircraft towing – were shared, while others, including de-icing, were carried out separately. However, due to the strict environmental regulations and complex compliance processes required at the new Munich Airport, it could no longer operate these services as a ‘sideline’ and therefore transferred those duties to EFM.
During its 20 years of service, EFM has become a famous name at the airport and its reputation has drawn customers and co-workers from numerous other facilities to see its remote de-icing set-up, which is the only one of its kind on this scale.
Though the decision about whether an aircraft needs to be de-iced remains the responsibility of its captain, the work is exclusively carried out by EFM.
EFM says it can perform up to 68 de-icing operations per hour on aircraft types that range in size from a Learjet to an Airbus A380. Flights are restricted between midnight and 05:00 local time, so EFM’s de-icing teams are on duty 24/7. The airport’s official de-icing season runs from early October until the end of April, but there are occasions when it might be necessary at other times. For example, when an aircraft lands in Munich after a long flight, the local air temperature may be +15°C, but the remaining fuel in the tanks has a temperature below -30°C. Should it rain during the aircraft’s turnaround time, the heat absorption of the cold fuel can lead to the formation of clear ice on the wings’ surface. Sometimes, this layer can be so smooth and transparent that it is invisible to the naked eye.
EFM estimates that approximately 94% of aircraft are de-iced just before take-off with their engines running at one of three special remotely placed de-icing pads near the end of each departure runway. A great effort is made to recover as much of the spent de-icing fluid as possible at these areas. EFM works in partnership with Clariant, which recycles the liquid so that it can be used again. Because the remote areas are so close to the runway, the treated aircraft can line-up and take-off almost immediately. It’s an near ideal situation as the quick departure minimises the chance that the hold-over time – that allowable before the de-icing fluid is rendered useless – will be exceeded, requiring the whole de-icing process to start again.
There are occasions when aircraft are de-iced on the apron; primarily when they require under-wing de-icing, or treatment outside the usual season. Propeller aircraft without propeller brakes and all propeller-driven GA aircraft are de-iced at their parking positions.
In short though, remote de-icing is preferable. It enables more fluid to be recovered and makes the departure process more efficient.
EFM sprays glycol-based de-icing fluids. The thin Type I fluid is diluted with water in a 55:45 mixture before being heated and applied to the aircraft at a temperature of 85°C that enables it to melt snow and ice. The anti-icing Type IV fluid has a thickener added to give it a higher viscosity that enables it to ‘stick’ to aircraft more easily. It is used cold, and undiluted and, as is the international practice, the two de-icing fluids are dyed different colours to prevent de-icing staff from accidentally getting them mixed up. The thinner Type I is orange, and the thicker Type IV is green. The hold-over time for each type of fluid is obviously dependent on the ambient temperature and precipitation levels. The colder the weather, the shorter the hold-over time.
The thin Type I fluid has a very short hold-over time, and is used at sub-zero temperatures when no freezing moisture – such as mist, fog or snow – is present. Under those circumstances only a single application is necessary, so it is known as the one-step process. However, if any form of freezing precipitation is present, the aircraft will require a higher level of protection so the two-step procedure is applied. This requires a first coating of Type I fluid to remove the existing ice, followed the Type IV to protect against the formation of new ice before departure. Obviously, if an aircraft’s take-off is delayed beyond its fluid’s hold-over time, the de-icing procedure must be repeated and the hold-over time then starts again.
When it entered service in 1993, Munich’s recycling facility for aircraft de-icing fluids was the first of its type in the world. Operated by Clariant, its continuing success enables EFM to achieve 70% of its annual requirements for Type I de-icing fluid through recycling.
The spent fluid that falls onto the de-icing pads is channelled – along with melted ice and snow – into large underground tanks. The mixture is then trucked to Clariant’s on-site recycling facility where it is cleaned during a series of mechanical and chemical refinement operations and then distilled to recover the basic glycol-based de-icing agent. Clariant then uses additives to produce Type I de-icing fluid which, after laboratory tests, can be used again.
According to Clariant, Munich’s EcoTain recycling system saves Munich Airport approximately €2 million (US$2.5m) every year. Before his recent departure, Dr Martin Westermaier, who was then Head of Application for Clariant, told Airports International that the savings come in two areas: the wastewater treatment of used de-icer effluent, much of which is avoided by recycling; and the need to buy less new de-icing fluids. “Recycling is a win-win-win for Munich Airport. The airport saves money and raw materials, and it reduces the environmental impact of its de-icing operation.”
Clariant said Munich’s system reduces the airport’s annual de-icing fluid purchases by about 2 million litres and lowers it carbon dioxide emissions by about 15,000 tonnes. The carbon savings are said to be roughly equivalent to the emissions of 64,000 round-trip flights between Munich and London. Not bad for a 20-year-old system.