Winter’s challenges

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A large proportion of the world’s airports have once again faced a difficult winter, doing all they can so that the worst of the weather doesn’t impede flight operations any more than is absolutely necessary. Generally, they have had a high degree of success in doing so

One gateway that can proudly boas   t that it has never closed its doors as a result of snow or ice on its runways is Chicago Rockford International airport. This gateway, less well-known than nearby Chicago O’Hare but still one of the 20 busiest cargo airports in the US as well as a domestic passenger service provider, has two teams of roughly a dozen individuals available to clear its 1.6 million square metres of pavement whenever snow and ice threaten operations. That huge area consists not only of runway, but also taxiways, ramps and even connecting roads.

In fact, says airport operations manager Zach Oakley, these teams – and the external contractors that are also called in on occasion – are employed as soon as there is even a trace of snow on the runway. They will work well before the conditions are a problem until well after there can possibly be a danger to flying, he outlines.

One team may be able to handle what Oakley describes as a smaller ‘event’, perhaps 5-10cm of snow, while everybody is called in for those prolonged, heavier snowfalls not unknown in this part of the US Midwest. These teams have worked for up to 32 hours to clear the tarmac during blizzard conditions, yet safety has never been threatened and the gateway has continued to remain operational in the worst of weathers.

The airport employs more than 20 pieces of heavy snow-clearing equipment, ranging from high-speed runway brooms to front end loaders and snow blowers. All of this heavy equipment is sourced from Oshkosh, the Wisconsin-based manufacturer.

Its most recent acquisition from Oshkosh was the purchase in 2008 of a new high-speed broom, but the airport operator intends to replace and upgrade much of its current snow clearing vehicle inventory. The airport will put a bid specification together on this and see what manufacturers can offer, Oakley explains.

One option being considered is the acquisition of more multi-functional equipment, vehicles that can handle the different tasks associated with snow clearance on just one chassis. Oshkosh offers such capability in its HT-Series Multi-Tasking Equipment (MTE), for example, snow tractors that can employ a wide range of ploughs, underbody scrapers, material spreaders, tow-behind brooms, or combinations thereof.

The snow that is removed by broom from Chicago Rockford airport’s pavement surfaces is pushed into windrows and then blown onto surrounding grass areas into snow-holding islands. It can then be hauled off-site if necessary, or simply left until the ambient temperature melts the snow.

Chilly Canada

North-east of Chicago is Canada’s Toronto Pearson International airport. This gateway typically has between 25 and 30 snow and ice-related ‘events’ a year – an event here meaning weather liable to affect airport operations. Toronto’s snow clearance teams, which number 189 in-house staff including seasonally employed personnel working on 24/7 operations as necessary, then go swiftly into action.

With up to a dozen clearances required a day during the worst of the winter weather, and a total of more than 2.7 million square metres of runway and taxiway supplemented by 1.5 million square metres of apron and stand space to clear, the job is a big one. And that doesn’t include nearly 2 million square metres of groundside airport connecting roads and car parks, clearance of which is handled by an outside contractor.

Toronto Pearson has five runways, all of which are cleared during an event, a process that the gateway calls ‘a full circuit’. As operator Greater Toronto Airports Authority (GTAA) manager apron maintenance Paul Schenk points out, the wind direction changes frequently at the gateway, requiring that cross-wind runways also be cleared and made ready for action.

Additionally, high-speed exits from the runways are cleared; it takes about 10-15 minutes for one of its strips to be handled by Toronto’s runway snow clearance team. Connecting taxiways are simultaneously cleared of snow and ice by other vehicles. As well as an array of trucks, sweepers and loaders used for dealing with the main runway, also part of GTAA’s snow clearance inventory of vehicles are smaller sweeps for areas such as passenger walkways, bridgeheads and GSE parks, as well as de-icing vehicles and a number of inspection vehicles that will test that the runway is safe for flight operations.

In fact, on the apron surface, GTAA has approximately 20 of its own trucks, sweepers and loaders. Complementing this array of heavy machinery owned by the airport operator are the vehicles to which GTAA has access according to the terms of a support contract with a private company. Used as required on a scaled approach, these vehicles are left on-site at the airport between 1 November and 15 April. The contract primarily covers front end loaders, backhoes, skid steers and labour crews.

While GTAA has not of late added to its snow clearing fleet of vehicles, it has been replacing them as required according to the operator’s five-year capital plan and appropriate lifecycle cost analysis, confirms Kevin Lacey, associate director of airfield operations.

Challenges in Eastern Europe

Over the course of the last two years, Warsaw Chopin International airport has been closed due to winter weather just three times and for a total of just four hours. Heavy snowfall and periods during which the temperature moves just above or below freezing are the biggest problem, says the Polish gateway’s spokesman, Przemyslaw Przybylski, and not the nation’s frequent harsh sub-zero conditions.

During the Warsaw winter, snow clearance work is carried out simultaneously on the airport’s runways, taxiways and apron. Snow is moved from runways and taxiways to the edge of the pavement, before being blown off the surface. As for the apron, snow is temporarily placed in assigned areas before being trucked to a dumping site.

Chopin’s snow-clearing convoy involves eight snow removal vehicles followed by two snow blowers, a sprinkler/spreader for de-icing chemical distribution and then finally friction-testing units.

To keep the operation going 24 hours a day when necessary, the airport authority can call on 19 snow removal vehicles (MB Actros 2041 truck tractors with a plough and Schörling P17, Oyeraasen RS 400 and RS 200 runway sweepers), Boschung BJB 8000 compact sweepers with sprinkler/spreaders, Schmidt runway sweepers supported by two Unimog tractors with snow ploughs and sprinkler/spreaders, other sprinkler/spreaders of various manufacture, along with four snow blowers and two JCB loaders/excavators for the loading and unloading of granulated chemicals.

New Overaasen snow removal sets were recently acquired in an initiative that has allowed the airport to reduce the time needed to clear its pavement from 40 to just 20 minutes, Przybylski adds.

Not a million miles from the polish capital is Germany’s Leipzig/Halle International airport and that facility too has to handle some extreme weather conditions. On average, it has to cope with about 30 days a year when its staff – of which there are approximately 270 available to work on a three-shift pattern – are asked to clear snow from pavement surfaces.

Explains René Kirsten, project manager winter service at the airport: “Clearing convoys consist of 13 vehicles; the tarmac is cleared from one side to the other, depending on the prevailing wind direction. The snow that is removed is loaded onto trucks and then transported to dumping areas.” Three friction testing vehicles are available for determining braking parameters following that.

Aebi Schmidt Deutschland manufactured about 95 percent of the specialised winter services equipment used by the airport operator, Kirsten notes, with a total of roughly 70 modern vehicles available at the gateway for snow clearing and gritting. Given this sizeable inventory: “The airport is not thinking of making any new purchases at the moment,” he adds.

Moscow Domodedovo

To the east of Leipzig and Warsaw is Moscow, whose Domodedovo International airport must also devote a lot of time and care to snow clearance if it is to operate through a harsh Russian winter.

On an average winter’s day, Domodedovo sweeps its runways at least twice, or as many times as required in order to keep the runways safe, a spokesperson explains. The gateway employs a fleet of vehicles that takes in a dozen Schmidt TJS 630 and two Bucher Schörling P-21S jet sweepers that are used to clear runways and taxiways. It has five snow blowers, Schmidt SUPRA 4001 and 5001 blowers and Oshkosh H2723Bs that can be operated on different power settings and are used according to the weather conditions and degree of snowfall.

Domodedovo also has eight CJS 914 compact jet sweepers that it uses on the apron in the restricted areas between aircraft stands and T-5 Continuous Friction Measuring Equipment (CFME) trailers for assessing the condition of the airport’s runways.

The airport has continued to invest in its snow clearing equipment. For the 2012-13 autumn and winter seasons it bought a total of 10 new pieces of equipment – two SUPRA 5001s, two CJS 914s, two TJS 630s and four B60-30 Stratos de-icing spreaders manufactured by Aebi Schmidt.

The frozen north

Given the Scandinavian climate, Swedish state-owned airport operator Swedavia is well practised in the arts and skills of snow clearance at the 11 gateways for which it is responsible. Indeed, according to Christian Nyberg (Stockholm Arlanda’s head of airside maintenance) and Ingemar Österlind (Arlanda’s manager runway & field maintenance), their teams clear runways at Sweden’s busiest airport about six times a day every winter.

With 3 million square metres of airside area at Stockholm Arlanda to be cleared, including three runways, taxiways, ramp, parking stands and transport routes for other vehicles, snow clearance at the capital’s air gateway is a full-time occupation. A 2cm snowfall on the terminal aprons can mean that some 1,200 lorry loads of snow must be carried to two snow dumps, which have a combined capacity of 400,000 cubic metres.

Stockholm’s snow clearance teams employ about 100 machines. On the runways and taxiways, combined plough, sweeper and blower vehicles are used, with up to 10 of these machines working in formation at any one time on runways. Smaller fleets of four vehicles might be used on aprons and three on taxiways.

De-icers follow the heavy plough/sweeper/blower vehicles on the runways, or a sand spreader might be employed.  Following on from the clearance operation, two friction testing cars are available to ensure that runways are ready for use. Stands are meanwhile cleared with different kinds of front loaders.

The water that is created from melted snow at the airport’s two snow dumps is collected in ponds and then transported by pipeline to a municipal water treatment plant.

Although snow clearance can of course disrupt flight operations, the airport never closes, Nyberg and Österlind declare. They point to the efficiency of snow clearance staff trained for three weeks before ever going airside, and a winter organisation that works in five shifts, 24/7 between October and April.

Keeping the runways operational during a Scandinavian winter is the result of collaboration between the airport’s snow co-ordinator, the apron tower and the airport technical and operative supervisor, with priorities based on the current traffic picture. Among the top priorities for clearance is the runway in operation, the taxiways serving that runway, aprons and parking stands as required and emergency routes from the fire station to the runway in operation. Next in priority come additional runways and taxiways, as well as relevant airside access routes.

Inevitability

It’s been that time of year again for numerous airports in the Northern Hemisphere to have to deal with the myriad of problems associated with snow, ice and freezing rain. Those that haven’t felt its impact this year may well do so in subsequent winters while, for some facilities, tough seasonal conditions can be guaranteed. As Chicago Rockford’s Oakley remarks of winter snow: “It’s coming, we just don’t know exactly when.”

Solar-powered snow clearance on tap

One company is taking the obvious fact that the sun melts snow on pavement to another level. The ICAX system collects heat from aircraft parking stands in summer by circulating water through an array of pipes embedded in the surface and transfers the heat below ground to where it is stored in what the firm calls ‘ThermalBanks’. The energy is moved to these ThermalBanks by, again, using water circulating through an array of pipes.

The system monitors the aircraft stand temperature and, if there is a danger of freezing, circulates heat back into the surface in order to maintain a temperature above freezing and so prevent any ice forming. Snow landing on the heated area of pavement will quickly melt.

While no airport has yet purchased the London-based ICAX Limited’s system, director Edward Thompson confirms that the company is “in discussion with a number of airports which see the advantages and accept that it works”.

The technology certainly does work: it is tried, tested and proven, he insists, having been employed in road surface applications in the UK. Using the system avoids the need for airports to employ polluting chemicals, grits or salts to control the melting point of snow and ice, plus ICAX is automatic and does not require manual labour to clear snow from beneath parked aircraft. And it is on the stands, underneath aircraft, that this system is perhaps most obviously beneficial, because heavy vehicles otherwise used for ploughing and/or de-icing on runways and taxiways cannot work underneath the wings of a parked aircraft.

Finally, while there are certainly installation costs, ongoing running costs are marginal. The advantages are many but no airport has yet committed itself financially to this technology. Whether we will see widespread use of ICAX or similar systems at the UK’s gateways, or others abroad, remains to be seen.

European contribution

Numerous European manufacturers are active in the production of dedicated airport snow clearance equipment. The division of Bucher (mentioned above) which is active in this sector was acquired by Swiss company Zaugg in 2010.  Along with Bucher Municipal’s snow sweepers sub-division came its Rolba snow blowers, the product lines thereby acquired said by Zaugg to represent a “perfect complement” to its own snow ploughs and snow blowers.

Aebi Schmidt is one of the biggest of many European companies to manufacture heavy airport snow clearance equipment. It offers a range of jet sweepers and blowers that are used at numerous gateways around the world, from as far afield as Xinjiang and Seoul Incheon in Asia, to Moscow Domodedovo and Helsinki in Europe. According to Mike Moore, Aebi Schmidt UK’s key accounts manager, Schmidt Airport Division has sold 650 jet sweepers and 400 cutter blowers to customers right around the world.

The company’s MS snow ploughs are supplemented by SUPRA rotating snow clearers and jet sweepers. Schmidt also offers de-icing sprayers and airport spreaders, and machines combining the two capabilities.

Sweden’s Volvo Construction Equipment is another manufacturer active in the field of airport snow clearance and it has worked in partnership with Aebi Schmidt in a large delivery of snow clearing equipment to Swedish airport operator Swedavia.

Operating an unusual model in its Original Equipment Manufacturer (OEM) solutions business, Volvo Construction Equipment offers Volvo chassis – or ‘part machines’ – on which OEMs can add their own snow clearing equipment as desired or required by the end user. Thus, Volvo’s A25 articulated hauler tractor unit has been supplied to Aebi Schmidt, which has added a sweeper, plough and blower for final equipment delivery to Swedavia.

The Swedish airport operator has 47 of these units, while Belgium’s Brussels airport is operating another three. A further three A25s have been delivered by Volvo to Aebi Schmidt for integration with its snow clearing equipment; these vehicles are also destined for Belgium.

According to Esbjörn Fritzell, global director business development at Volvo Construction Equipment, these Aebi Schmidt snow sweepers are thus not only extremely capable but also extraordinarily reliable, boasting a 99 percent ‘up-time’.

The OEM business model has the virtue of allowing Volvo to gain incremental revenue on equipment types in which it has particular expertise. It allows Volvo to leverage its existing products, Fritzell notes, not least through partnering with companies such as Aebi Schmidt.

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