A glider winch launch puts massive stress on every component—cables under thousands of pounds of tension, propane-fuelled power packs running at full throttle, and guillotine mechanisms that must cut cleanly every time. A failed cable, seized roller, or empty gas tank doesn't just scrub a launch—it can cause a catastrophic cable break at altitude. This comprehensive sky launch winch and tractor checklist covers every critical step from tractor fluids and towing attachments through winch chassis, power pack run-up, propane refuelling, and end-of-day shutdown, keeping your club's launch operations safe and airworthy every flying day. Start your free fleet trial
Sky Launch Winch & Tractor Checklist
Glider Winch Launch Operations — Pre-Start • Run-Up • End of Day
Checklist Purpose
Launch Safety
- A winch launch generates extreme cable tension while accelerating a glider from standstill to flying speed in seconds. Every component in the chain—cable, parachute, shock rope, drums, guillotine, and power pack—must be verified before the first launch. A single failed component can cause a cable break at altitude, leaving the pilot with a critical low-level emergency.
Equipment Reliability
- Winch power packs run at extreme RPM on propane fuel with tight-tolerance transmissions and cooling systems. Low oil, slack belts, or insufficient coolant can seize the engine mid-launch. Pre-start checks on fluids, belt tension, and transmission condition prevent expensive power pack failures and keep your club launching all day.
Club Compliance & Records
- Gliding clubs operate under national aviation authority oversight. Documented daily inspections, maintenance logs, and guillotine certifications demonstrate airworthiness compliance. The DI booklet and maintenance log provide a traceable record that protects the club, the winch driver, and the duty instructor in the event of an incident investigation.
1. Tractor (Prime Mover)
Check the tow vehicle fluids, tyres, and towing connections before moving the winch:
Fluids
Wheels & Tyres
Towing
2. Winch Maintenance Log
Review the maintenance log and DI booklet before physically inspecting the winch:
Log Review
Why This Matters
- The maintenance log is your first line of defence — it tells you what was reported on the last flying day, whether the guillotine certification is current, and if any defects are awaiting repair. Never skip straight to the physical inspection without reading the log first. An outstanding defect that wasn't resolved could make the winch unserviceable.
Guillotine Certification
- The guillotine is the winch's most critical safety device — it must cut the cable cleanly on demand if a launch goes wrong. Monthly inspection includes checking blade sharpness, mechanism travel, spring tension, and lubrication. If the monthly certification has lapsed, the winch must not launch until a full guillotine inspection is completed and signed off.
3. Winch Chassis
Inspect the winch chassis, cab, rollers, brakes, and cable gear for safe operation:
Chassis Condition
Rollers & Brakes
Cable Gear
Book a demo to digitize winch cable & roller inspection records
4. Chassis Rear Housing
Inspect the winch drums, differential, cable drum brakes, and propane tank levels:
Drums & Drive
Brakes
Fuel
5. Winch Power Pack
Check all power pack fluids, belts, and components for reliable launch power:
Cooling & Belts
Engine Fluids
Why Power Pack Checks Are Critical
- The power pack delivers maximum power for 30–45 seconds per launch with minimal cool-down between runs. Low oil causes bearing failure. Slack belts cause overheating. Low transmission fluid causes slipping under load. Any of these failures during a launch can result in an underpowered climb or sudden power loss—leaving the pilot in a dangerous low-altitude situation with no energy to recover.
6. Propane Gas Refuelling
Follow the correct procedure for safely refuelling the winch propane tanks:
Setup & Connection
Filling Procedure
Disconnect & Secure
7. Power Pack Run-Up
Start the power pack and verify all systems before the first launch of the day:
Start-Up Sequence
Communications & Visibility
Spares & Tools
Track power pack run hours & service intervals with Fleet Rabbit
8. DI Booklet Sign-Off
Complete the daily inspection record and report to the Duty Instructor:
Sign-Off
Before First Launch
Communication Confirmed
9. End of Day Shutdown
Complete all shutdown, securing, and record-keeping tasks after the last launch:
Winch Shutdown
Equipment Return
Records & Security
Streamline Glider Winch Operations
Fleet Rabbit's Winch & Ground Equipment Benefits:
- ✓ Digital DI records with operator sign-off, witness signatures & photo evidence
- ✓ Automated alerts for guillotine monthly inspections, belt replacements & oil changes
- ✓ Track power pack run hours, cable replacement schedules & propane consumption
- ✓ Instant defect notifications to club maintenance officer with priority flagging
- ✓ Aviation-grade inspection records stored securely in the cloud for authority audits
Common Hazards to Watch For
Guillotine Mechanism Failure
- Cable Won't Cut: The guillotine is the winch's emergency cable release — it must sever the cable instantly if a launch goes wrong or the cable wraps around the drum. A seized, dull, or poorly lubricated guillotine that fails to cut means the cable stays connected when it shouldn't. Monthly inspections must verify blade sharpness, spring tension, mechanism travel, and lubrication. If the guillotine hasn't been inspected this month, the winch is unserviceable — no exceptions.
Cable Drum Wire Locking Failure
- Wire Detachment: The wire locking on the main drum hubs is all that keeps the cable attached to the drum under thousands of pounds of tension during a launch. If the locking mechanism is worn, damaged, or improperly seated, the cable can detach from the drum mid-launch — resulting in complete and instant loss of tension with the glider at a critical altitude. Check wire locking on both hubs and inspect guide rings for wear or damage before the first launch every day.
Propane System Leak
- Gas Accumulation: Propane is heavier than air and pools in low spots — including the winch chassis and cab floor. A leaking valve, loose connection, or damaged hose allows propane to accumulate undetected until an ignition source triggers a flash fire or explosion. After refuelling, check all connections with soapy water solution for bubbles. Smell test around valves before starting the power pack. Gas taps should be finger-tight only — overtightening damages valve seats and causes leaks.
Winch Launch Safety: Why Pre-Flight Equipment Checks Matter
Understanding the forces and risks involved in glider winch launching explains why every checkpoint on this list exists:
Launch Forces & Stresses
- A typical winch launch accelerates a glider from 0 to 60+ knots in under 10 seconds, pulling 1,000–2,500 lbs of cable tension through the entire system. The power pack, transmission, drums, cables, rollers, parachutes, and shock ropes all absorb this force dozens of times per flying day. Component fatigue is cumulative — what passed inspection last week may have reached its failure point today. That's why daily checks are non-negotiable.
Cable Break Scenarios
- A cable break during a winch launch is one of the most critical emergencies in gliding. The pilot suddenly loses all towing force at low altitude and must react immediately — either landing ahead or executing a modified circuit. Worn cables, damaged shackles, corroded grommets, and eroded roller housings all increase break risk. Pre-start inspection of every cable component directly reduces the probability of this life-threatening situation.
Winch Driver Responsibility
- The winch driver holds the safety of every pilot they launch in their hands. A thorough pre-start check isn't bureaucracy — it's the driver's personal verification that they're confident the equipment is safe to launch. The DI booklet signature means "I have checked this winch and I am satisfied it is serviceable." That signature carries weight with club management, the national authority, and in any incident investigation.
Essential Inspection Tools
Equip your winch team with the right tools for thorough pre-start verification:
Measurement & Testing
- Tyre Pressure Gauge: For tractor and winch chassis tyre checks.
- Belt Tension Gauge: For verifying 25mm deflection on power pack belts.
- Brake Pad Gauge: For measuring cable drum calliper pad thickness.
- Propane Leak Detector: Soapy water solution or electronic gas detector.
Cable & Hardware
- Cable Inspection Gloves: For running cable through hands to feel for broken strands.
- Magnifying Glass: For inspecting shackle pins, grommets & cable attachments.
- Feeler Gauge Set: For checking guillotine blade clearance.
- Cable Repair Kit: Spare shackles, grommets, weak links & swaging tools.
Documentation
- DI Booklet: The legally required daily inspection record.
- Maintenance Log: For cross-referencing previous defect entries.
- Guillotine Inspection Record: Monthly certification tracking.
- Digital Camera: For documenting defects — or use Fleet Rabbit's in-app photo capture.
Sky Launch Winch & Tractor FAQs
1. How often should a winch launch system be inspected?
A full pre-start inspection is required before every flying day — covering the tractor, winch chassis, power pack, cables, and propane system. Monthly inspections must include a full guillotine mechanism check with lubrication. Annual inspections should cover structural chassis assessment, power pack overhaul, full cable replacement evaluation, and transmission service. The DI booklet must be signed before the first launch and updated with any defects at end of day. Start a free Fleet Rabbit trial to automate daily, monthly, and annual inspection scheduling for your club's ground equipment.
2. Why is the guillotine inspection checked monthly?
The guillotine is the winch's emergency cable release mechanism — it must cut the cable cleanly and instantly on demand. During a drum wrap, tangled cable, or emergency stop, the guillotine is the only thing that prevents the cable from causing serious damage to the winch or the glider. Monthly checks verify blade sharpness, spring tension, full mechanism travel, and proper lubrication. A dull blade or seized mechanism that fails during an emergency can have catastrophic consequences.
3. How do I check cable gear before the first launch?
Inspect the shock ropes for fraying, parachutes for tears and tangled lines, and all cable attachments (shackles, grommets, weak links) for deformation or corrosion. Run the cable through gloved hands feeling for broken strands or kinks. Any misshapen shackle or worn grommet must be replaced — not re-used. Check that weak links are the correct rating for the glider types being launched that day. Cable gear takes enormous cyclic loading and degrades incrementally — what looked fine three flying days ago may have reached its replacement threshold.
4. What is the correct propane refuelling procedure?
Move to the storage area and secure the tractor and winch with handbrake and gears. Wear gloves when connecting the hose. Open the storage tank valve and the winch tank valves (anti-clockwise to open). Fill the top tank to minimum ¾ full — the tanks equalise automatically. Close the bowser valve after filling, disconnect the hose, and secure it. Use finger-tight pressure only on all gas connections — overtightening damages valve seats and causes leaks. Book a Fleet Rabbit demo to track propane consumption and refuelling logs digitally.
5. What does the pay-out brake check involve?
The pay-out brake controls cable tension during the retrieve phase. Operate the brake lever a couple of times to re-establish any loss in hydraulic pressure — you should feel firm resistance building. Then check the main drum: with the brake applied, you should still be able to move the drum with hand pressure (it's not a full lock). This confirms the brake is providing controlled tension rather than either free-wheeling (dangerous) or fully locked (which would prevent cable pay-out during launch).
6. What should I check during the power pack run-up?
After selecting the main power switch to ON: start the engine and immediately watch the oil pressure light — it should go out within seconds. Let the engine idle and walk around the power pack bay checking for fluid leaks, unusual noises, and loose or vibrating belts. Check that the water temperature gauge begins to rise normally. Verify radios, cab lights, and horns all work. Clean all windows for maximum visibility during launches. Finally, confirm the toolbox and cable repair kits have sufficient spares for the day.
7. Why does the end-of-day checklist include a personal training log update?
The personal winch training log documents your experience, launch counts, and any exceptional events like launch failures, cable breaks, or equipment issues. This record tracks your proficiency development and is reviewed during currency checks and re-authorisations. Recording incidents immediately while details are fresh provides accurate data for club safety reviews. It also demonstrates your commitment to safe operations — which matters when the club reviews winch driver authorisations. Use Fleet Rabbit to maintain digital training logs alongside equipment inspection records.
8. What are the most common reasons a winch is declared unserviceable?
The top reasons are: lapsed guillotine monthly inspection, low differential oil, worn cable drum brake pads, damaged cable gear (frayed shock ropes or misshapen shackles), and propane system leaks. Many of these are discovered during the pre-start check and can be resolved on the day if spares and tools are available. However, a lapsed guillotine inspection or structural chassis defect means the winch cannot launch until a qualified person completes the required work and signs off the DI booklet.
Standardize Glider Winch Launch Operations
Paper DI booklets get coffee-stained, guillotine inspection records go missing, and cable defects get mentioned verbally but never documented. Fleet Rabbit gives your winch team a mobile-first daily inspection app that captures every checkpoint — tractor, chassis, power pack, cable gear, propane levels, and end-of-day shutdown — with timestamped photos, operator and witness signatures, and aviation-grade cloud records that are ready for authority audits before the first cable is pulled.
