1. Cost per aircraft-out-of-service hour
For most operators the airframe earns nothing while it sits in the wash bay. Record, for each wash event, the time from aircraft arrival to release back to service — including set-up, masking, waiting for water temperature, dwell time for chemicals, rinsing, drying and inspection. Then divide the crew cost of that window by the number of people on task. Facilities that skip this measurement tend to compare two machines on throughput while ignoring the queue time between aircraft, which is frequently the longer cost.
Ask what the method changes about that window. A steam cleaning machine heats water on board rather than relying on a boiler loop or pre-heated supply, so a wash can start as soon as the aircraft is chocked. Higher vapor pressure means the crew spends its time on mechanical action and dwell rather than on scrubbing harder. In facilities where hot supply water is unavailable or arrives intermittently, on-board heating removes a scheduling dependency that would otherwise push aircraft into overtime shifts.
2. Water, containment and discharge
Water cost at an airfield is rarely just the metered volume. It is the volume multiplied by the containment requirement: bunded wash pads, recovery channels, oil-and-silt separators, and the paperwork proving that wash water did not enter a storm drain. High-volume pressure washing multiplies all of that, because more runoff means more treatment and more sampling.
Evaluate methods on litres of runoff generated per aircraft, not litres sprayed. Low-water steam systems clean by transferring heat and vapor pressure into the soil, so the film left on the surface is thin and the recovery volume is correspondingly small. That changes the containment design conversation: a smaller collection footprint, less separation capacity, and fewer disposal loads per month. Where a facility is negotiating wash-area consent with an airport authority or a local regulator, runoff volume is often the number that decides the outcome.
3. Chemical consumption and surface risk
Track three chemical numbers: drums purchased per aircraft, dwell time each product requires, and the number of surfaces where the product is not permitted. Aviation soils are mostly hydrocarbon — exhaust residue, grease, fuel film, insect remains on leading edges. Solvent and alkaline detergent programmes attack that soil with chemistry and time; heat attacks it with energy. Facilities relying on aggressive detergent for carbon deposits also carry the risk cost of stripped coatings, dulled finishes and damaged composite or decal areas, which lands in the maintenance budget rather than the cleaning budget.
A method that lifts grease with temperature and pressure reduces both the chemical line item and the re-coating exposure. This is where the specification of industrial steam cleaning equipment matters: steam temperature and vapor pressure are the working parameters, so compare those published figures between machines, and confirm that the unit supplies a controlled range rather than a single maximum. Crews also need to know how the machine switches between a drier steam for sensitive areas and a wetter steam for heavy soil.
4. Labour and equipment utilisation
Wash crews are rarely fully occupied. Much of a shift is spent moving equipment, filling tanks, waiting for water to heat, and re-washing areas where residue redeposited. Cost per aircraft should therefore be calculated with crew idle time included, not with the theoretical wash time only.
Mobility and power supply decide how much of the shift is productive. A self-contained unit with its own heating and tank reduces hose runs and plumbing constraints, which is the difference between washing on a fixed pad and washing wherever the aircraft is parked. For facilities with limited apron space, a mobile, battery-capable aircraft exterior cleaning equipment setup lets two smaller teams work separate aircraft instead of one crew queued behind a single wash point.
5. Downtime, spares and audit exposure
A cleaning programme that stops mid-shift has a direct cost in delayed departures. Price the equipment accordingly: warranty terms, service response, availability of heaters, pumps, seals and control parts, and whether consumables are proprietary or standard. Protection features on the machine — for leakage, short circuit, high temperature and water shortage — reduce both fault rate and the incident report that follows a fault near an aircraft.
Audit exposure sits in the same budget line. Insurers, airport operators and food-safety or hygiene auditors increasingly ask for records of what was used, how much water was discharged, and how staff are protected. A method that reduces solvent use and runoff volume reduces the volume of evidence the facility has to collect and defend.
A simple evaluation worksheet
Take one month of existing data and fill in these six rows before talking to any supplier:
- Aircraft out-of-service hours per wash, start to release, averaged over ten events
- Crew-hours per wash, including travel, set-up and waiting time
- Litres of runoff captured or discharged per aircraft
- Detergent and solvent spend per aircraft, plus dwell minutes it requires
- Rework rate: aircraft needing a second pass, and the cause recorded each time
- Unplanned equipment stoppages per month and hours lost
Compare each candidate method against those rows rather than against a headline machine price. A unit that costs more to buy but removes waiting time, cuts chemical dwell and halves runoff will beat a cheaper machine within one quarter of operation, and the worksheet shows it to whoever signs the purchase order.
What to ask the supplier
Request the published steam temperature and vapor pressure for the model, tank capacity, power supply required, and the protection functions listed for the machine. Ask which variants are supplied with a battery for mobile use and which are fixed installations, and confirm the configuration you are quoting matches the datasheet. If your wash area has constraints on power connection, runoff capture or working hours, put those constraints in writing at the enquiry stage so the proposal addresses them.
Shenzhen PowerDe Automation Precision Equipment Co., Ltd. builds cleaning equipment in Shenzhen and publishes the technical parameters for each model on its product pages, including heating power, steam temperature, vapor pressure and tank capacity. Send your worksheet figures with the enquiry and the engineering team can size the unit and the wash process to your aircraft turnaround profile instead of recommending a catalogue default.
