Brightwork Polish at Sion (LSGS)

Why does brightwork oxidise faster in the Alps?

Altitude and moisture accelerate the dulling of bare metal. Sion sits at 1,582 feet in the Rhone Valley, but the approaches thread between peaks that rise above 10,000 feet, and aircraft often climb or descend through cloud layers that leave a film of condensation on cold-soaked leading edges and inlet rings. When the airframe warms on the apron, that moisture evaporates, but the salts and minerals in Alpine air—lifted by valley winds—remain on the metal and begin the oxidation cycle.

Winter compounds the problem: de-icing fluid, snow-melt runoff on the ramp and the fine grit thrown up by propwash all leave residue on polished surfaces. A spinner that gleamed in October will show a haze by February if it has flown a dozen sectors without a wash. Engine exhaust staining, already persistent, bakes harder in the temperature swings between cold overnight and midday sun on the apron. Hangar space is available for visiting aircraft up to 77,000 kilograms, and detailing work under cover means the metal can be brought to a stable temperature before polishing begins, which improves the bond of the sealant applied afterward.

What changes at Sion for a third-party detailing crew?

The aerodrome administration operates from April to September between 05:00 Zulu and the end of daylight—no later than 18:00 Zulu—and from October to March between 07:00 and 19:00 Zulu, though actual closing time tracks the sunset. No night operations are permitted, and flights outside administration hours require prior permission. The two FBOs, Signature and Alpinejet, staff their terminals from 07:00 to 20:00 local in summer and from 08:00 until nightfall in winter, which shortens the working day for any activity that needs handler coordination or airside access.

Airside ramp access is controlled: the airport operates 24-hour surveillance, and entry requires either an airport identity card—which in turn requires a police record extract—or a handler escort. Customs and immigration are on site and available during aerodrome administration hours. A third-party crew arriving to polish brightwork will coordinate entry through the handling agent, who arranges the escort and confirms the stand or hangar position. If the aircraft is scheduled to depart before the work is finished, the handler will relay slot or PPR constraints; Sion is not slot-coordinated, but special permission is needed for any movement outside the published hours, and that timeline governs how much can be done in a single visit.

How is Brightwork Polish scheduled at Sion?

Most brightwork work here is recurring rather than reactive. Flight departments running a regular shuttle to Crans-Montana or Verbier will add a polish to the schedule two to four times a year, often at the start and end of the ski season, and the handler books hangar time if the weather forecast shows snow or freezing rain. One-off requests usually follow a decon or a complete detail: an operator notices that the leading edges or inlet rings have lost their lustre during a series of short hops, and the polish is added to a layover that was already planned for a cabin refresh or an exterior correction.

Duration runs from one to three days depending on the amount of bare metal. A mid-size jet with polished leading edges, two inlet rings and exhaust bezels will occupy a day and a half if the oxidation is light; if the metal has been neglected and needs compounding before the final polish, the work stretches to two full days. Ultra-long-range aircraft with extensive bright trim—window surrounds, cheat-line accents, nacelle bands—can fill three days. The sealant application adds two to four hours at the end, and the aircraft must remain stationary until the sealant cures, which the handler factors into any departure slot or PPR filing.

What does the handler expect when brightwork polish is booked?

The handling agent wants three pieces of information before the crew arrives: the scope of the polish (which surfaces, and whether compounding is expected), the preferred location (ramp stand or hangar), and the departure schedule. Scope determines how many team members will work and what consumables to stage; location affects whether GPU or external lighting is needed; departure schedule tells the handler when to file for any movement outside normal hours or when to release the stand for another aircraft.

If hangar space is requested, the handler will confirm availability and dimensions—Signature operates a 67,200-square-foot hangar, and Alpinejet offers hangar storage—and will coordinate towing if the aircraft is not positioned there on arrival. Ramp work is straightforward in summer, but from October onward the handler will monitor the weather: if snow or freezing conditions are forecast, the work either moves indoors or is postponed. The handler also arranges the airside escort for the detailing crew, confirms that all tools and materials clear the security screening, and logs the activity in the airport's movement record so that any extension or early finish can be communicated to aerodrome administration without delay.

Which surfaces are included in a brightwork polish?

Wing and stabiliser leading edges are the priority: these are the first surfaces to show oxidation because they meet the airflow head-on and collect moisture, insects and exhaust soot on every flight. The metal is polished in stages—cutting compound to remove the oxide layer, finer polish to bring up the shine, then sealant to slow the next cycle. Engine inlet rings and spinners follow the same sequence, though exhaust staining around the lip of the inlet often requires a solvent wipe before polishing begins.

Exhaust and thrust-reverser surfaces are next. Carbon deposits bake onto the metal at high temperature, and if left for more than a few weeks they bond hard enough that compounding alone will not shift them; a chemical cleaner is applied first, then the surface is polished and sealed. Window surrounds and any bright trim—door handles, cheat-line accents, registration-letter backing—are polished last. These areas are smaller but conspicuous, and the contrast between polished and neglected metal is obvious to anyone standing at the airstairs. The sealant application covers every polished surface and is left to cure before the aircraft is released; the handler will confirm that no rain or snow is forecast during the curing window, which usually runs two to four hours depending on temperature and humidity.

How does ski-season traffic affect detailing work at Sion?

Business aviation peaks in winter when the Valais resorts—Crans-Montana, Zermatt, Verbier, Nendaz, Veysonnaz, Saas-Fee—are in full season. The two FBOs see a surge in arrivals from December through March, and hangar space, GPU availability and handler time all come under pressure. A brightwork polish booked during this period needs to be confirmed weeks in advance, and any request for hangar work will compete with overnight storage for transient aircraft whose operators want the airframe protected from snow and ice.

The compressed working day adds another constraint: from October to March the FBOs staff their terminals from 08:00 until nightfall, and aerodrome administration closes at the end of daylight, no later than 19:00 Zulu. A three-day polish must be split across three short days rather than two long ones, and if the departure is scheduled for early morning the final sealant cure must finish the evening before. Recurring customers—flight departments running a dedicated shuttle or charter operators with a seasonal base—will build the polish into a maintenance window at the start of the season, when the aircraft arrives clean, and again in March before it repositions, so that the brightwork is protected through the heaviest period of exposure and then restored before the summer programme begins.