4 The Safe Winch Launch campaign has contributed to a significant reduction in winch accidents since 2006.6 year periodFatal or serious injury winch accidents4 (none in 2010 or 2011)18Average 6 year period
5 All Winch Accidents,The main improvement is due to fewer stalls and spins on the wire or after a launch failure6 year aggregates show no improvement in cable encounters and wingdrop/ groundloop/ cartwheelLet’s look at all winch accidents, including the minor ones.Again we see a reduction in stall/spin accidents. There is no reduction in accidents following a wing drop. Encounters with the launching cable continue.
6 For advice on minimising cable encounters, please check out the Winching Operations presentation, also contained on this DVD
7 The aim of this presentation is to help you to stop wing drop accidents whether you are in the glider or not
8 What is the Existing Advice to Pilots? Start the launch with your hand ON the releaseIf you cannot keep the wings level, release immediatelyAny further details?Make sure you have a firm grip on the release. The force required to release under tension on the ground is high. Any gloves being worn should provide good grip, otherwise remove them
9 What Does the BGA Instructor Manual Say? Four factors which may cause a swing during the ground run are listed. A swing may lead to a wingdrop and groundloop These factors are....
10 Crosswind/Weathercock Offset cable/Bow in cableOffset winch hookWhich wing is being held
11 Considered individually, these factors are well understood.... In a crosswind, the glider will tend to weathercock into windAn offset cable will cause the glider to swing towards the cableAn offset hook will cause the glider to swing away from the side with the hookHow the wing runner influences any swing depends on their technique, but they typically hold their wing back slightly
12 The following diagram from the Instructor Manual shows two of these factors - Offset Cable and Offset Hook The severity of any swing depends on the amount of offset, and the acceleration provided EXCESSIVE ACCELERATION = RAPID SWING PROGRESSIVE ACCELERATION = CONTROLLABLE SWING
14 Of course, all four of these factors causing swings interact Of course, all four of these factors causing swings interact. This may cancel out, or increase the swingIf we understand and reduce wing drops and swings, we can reduce groundloops and cartwheels
16 Some accident reports stated that the cable was released as soon as the wing touched the ground, but the glider still groundlooped, often causing significant damageSo to keep your glider and pride undented, your target is to release BEFORE the wing touchesIf a wing starts to drop, and you can’t catch it with opposite aileron, RELEASE!
17 Accident reports show that once a wing drops and the glider starts to yaw, the groundloop develops rapidlyThe only way out is to release before this happens – otherwise you are just along for the ride!
18 Being pushed back into the queue after releasing the cable is significantly less embarrassing than bending a glider
20 Assess the wind, cable and hook position to anticipate if a wing drop or swing is likely to occur Learn from the preceding launches by watching if any wing drops or swings occurEnsure glider is aligned correctly with winch and cable run before accepting the cable:If cable run is offset, pointing the glider slightly away from the winch and towards the offset cable can reduce the swing (see following diagrams)If glider is offset from cable by more than one wingspan, move the glider closer before launch
23 If the wing runner is holding your wing at the wrong height, or is struggling in a gusty wind, release before Take Up Slack and discuss it. A small aileron adjustment, or asking the wing runner to hold the wing at a different height, may make their job much easier. It will also reduce the chances of a wing dropKnow the crosswind limits for your glider. If you are operating near those limits, plan your launch carefully and be ready to release early if a wing starts to go down
24 If you have a preference for which wing is to be held in a crosswind, brief the wing runner accordingly, but bear in mind which side of the glider the cables have been brought to. The wing runner should NOT be close to a cable when running your wingA surprising number of wing drop accidents occur when the wind is close to a direct headwind – be alert in all conditions
25 Which Wing Should Be Held? There is no rule for all situationsIt is important for the wing runner to be safely separated from the live cable and other cablesIf a weathercock is likely, running the downwind wing will help to control any swing into windIf a swing towards an offset cable is likely, running the wing furthest from the cable will helpIf a swing away from an offset hook is likely, running the wing on the same side as the hook will help to control the swing
26 Which Wing Should Be Held? In a strong, blustery wind which makes holding the wing difficult, running the upwind wing can help reduce the chance of a wing dropIn crosswinds, the upwind wing should be slightly lowerThese factors interact – assess the dominant factor
27 Monitor Wings Level Throughout If you wait until you feel the wing touch the ground and start dragging, it may be too lateEnsure you can assess “Wings level?” and know what bank angle is unacceptableAcceptable bank angle is relatively smallSome glider types will have a wing tip on the ground before reaching even 10o of bank
29 Airfield and Glider Fleet Cut grass short and keep it shortChoose launch point position to minimise undulating ground and cross-slopesFull use of airfield to minimise crosswindReliable, clear signalling system with 2 methods of providing a STOP signal – ideally visual and aural (e.g. lights + buzzer/radio)
30 Attaching the CableEnsure gliders are aligned correctly with winch and cable runAsk pilot if any water ballast or special infoDon’t just take the rings to the glider – Pull the parachute across in line with gliderLaunching on downslope? Arrange a tail holder if required
31 Wing RunnerWings should look level, or in a crosswind the upwind wing should be slightly lowWings should feel balanced, especially with water ballast or crosswind – find the balance pointLook at ground clearance on BOTH wing tips to assess if wings are levelOn a cross-slope, ensure uphill wing tip isn’t too close to the groundIf fighting wing-tip in a strong wind, delay launch and try holding wing tip at a different height, ask pilot to change aileron position, or both
32 Wing Runner RUN WITH THE WING! Don’t just take a couple of steps and let go!KEEP THE GLIDER STRAIGHT!Your job isn’t just to keep the wings level, but also to keep the glider straightRun “with” the glider. Don’t run forwards before the winch accelerates. Don’t hold your wing backIf the glider tries to swing, often a small correction from the wing runner is all that is needed until the cable is straight and the forces line up
33 Launch Signaller Glider aligned correctly with winch and cable? Allow wing runner time to balance wings before signalling – If they are struggling, delay signalsWait for cable to pull across and glider to creep forwards before giving All OutEarly All Out can cause a swingIf a wing drops, simultaneously apply STOP light and make a loud radio call to the winch
34 Winch Driver – Take Up Slack Take Up Slack at correct speed – slow walkAssess by glancing at drum/pulley/cable/shaft..Fast Take Up Slack can jerk wing out of wing runner’s hand before All Out. Wing then dropsIf drum stops during Take Up Slack it can lead to an early All Out signal which can cause a swing. Keep the drum rotating if neededCorrect engine idle speed can ensure consistent Take Up Slack speed with most winch types
35 Winch Driver – All OutExcessive acceleration may reduce the chance of a wing drop in some situationsBUT if a wing has already started to go down, or the cable or hook are offset, it will increase the forces causing the potential groundloop, and reduce the time to reactThe key is prompt reaction to All Out, but to accelerate at the normal rateFor more info on acceleration see Winch Operations presentation on this DVD
36 All pilots and members of the launching team can contribute to reducing groundloop and cartwheel accidents during winch launches
37 Can we manage to STOP THE DROP from 2013 onwards?