safe winch launching stop the drop! bga safe winch launching initiative

Safe Winch Launching

STOP THE DROP!

BGA Safe Winch Launching Initiative


LET’S ELIMINATE WINCH LAUNCH GROUNDLOOPS AND CARTWHEELS.....


IS THERE A PROBLEM?


The Safe Winch Launch campaign has contributed to a significant reduction in winch accidents since 2006.

6 year period Fatal or serious injury winch accidents

2006-2011 4 (none in 2010 or 2011)

2000-2005 18

Average 6 year period 1976-2005 18


All Winch Accidents, 2006-2011

• The main improvement is due to fewer stalls and spins on the wire or after a launch failure

• 6 year aggregates show no improvement in cable encounters and wingdrop/ groundloop/ cartwheel


FOR ADVICE ON MINIMISING CABLE ENCOUNTERS, PLEASE CHECK OUT THE WINCHING OPERATIONS PRESENTATION, ALSO CONTAINED ON THIS DVD


THE AIM OF THIS PRESENTATION IS TO HELP YOU TO STOP WING DROP ACCIDENTS WHETHER YOU ARE IN THE GLIDER OR NOT


What is the Existing Advice to Pilots?

• Start the launch with your hand ON the release• If you cannot keep the wings level, release

immediately

Any 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


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....


• Crosswind/Weathercock• Offset cable/Bow in cable• Offset winch hook• Which wing is being held


Considered individually, these factors are well understood....•In a crosswind, the glider will tend to weathercock into wind•An offset cable will cause the glider to swing towards the cable•An offset hook will cause the glider to swing away from the side with the hook•How the wing runner influences any swing depends on their technique, but they typically hold their wing back slightly


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 SWINGPROGRESSIVE ACCELERATION = CONTROLLABLE SWING

Safe Winch LaunchingDiagram courtesy of Steve Longland


• Of course, all four of these factors causing swings interact. This may cancel out, or increase the swing

• If we understand and reduce wing drops and swings, we can reduce groundloops and cartwheels


ANY USEFUL LESSONS FROM ACCIDENT REPORTS?


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 damage•So to keep your glider and pride undented, your target is to release BEFORE the wing touches•If a wing starts to drop, and you can’t catch it with opposite aileron, RELEASE!


Accident reports show that once a wing drops and the glider starts to yaw, the groundloop develops rapidly

• The only way out is to release before this happens – otherwise you are just along for the ride!


Being pushed back into the queue after releasing the cable is significantly less embarrassing than bending a glider


SO, HOW CAN PILOTS AVOID WING DROP ACCIDENTS?


• 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 occur

• Ensure 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

Safe Winch LaunchingDiagram courtesy of Steve Longland


• 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 drop

• Know 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


• 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 wing

• A surprising number of wing drop accidents occur when the wind is close to a direct headwind – be alert in all conditions


Which Wing Should Be Held?• There is no rule for all situations• It is important for the wing runner to be safely

separated from the live cable and other cables• If a weathercock is likely, running the downwind

wing will help to control any swing into wind• If a swing towards an offset cable is likely, running

the wing furthest from the cable will help• If 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


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 drop

• In crosswinds, the upwind wing should be slightly lower

• These factors interact – assess the dominant factor


Monitor Wings Level Throughout

• If you wait until you feel the wing touch the ground and start dragging, it may be too late

• Ensure you can assess “Wings level?” and know what bank angle is unacceptable

• Acceptable bank angle is relatively small• Some glider types will have a wing tip on the

ground before reaching even 10o of bank


WHAT ELSE CAN WE ALL DO TO HELP?


Airfield and Glider Fleet

• Cut grass short and keep it short• Choose launch point position to minimise

undulating ground and cross-slopes• Full use of airfield to minimise crosswind• Reliable, clear signalling system with 2

methods of providing a STOP signal – ideally visual and aural (e.g. lights + buzzer/radio)


Attaching the Cable

• Ensure gliders are aligned correctly with winch and cable run

• Ask pilot if any water ballast or special info• Don’t just take the rings to the glider – Pull the

parachute across in line with glider• Launching on downslope? Arrange a tail

holder if required


Wing Runner• Wings should look level, or in a crosswind the upwind

wing should be slightly low• Wings should feel balanced, especially with water

ballast or crosswind – find the balance point• Look at ground clearance on BOTH wing tips to assess

if wings are level• On a cross-slope, ensure uphill wing tip isn’t too close

to the ground• If 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


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 straight• Run “with” the glider. Don’t run forwards before

the winch accelerates. Don’t hold your wing back• If 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


Launch Signaller

• Glider aligned correctly with winch and cable?• Allow wing runner time to balance wings

before signalling – If they are struggling, delay signals

• Wait for cable to pull across and glider to creep forwards before giving All Out

• Early All Out can cause a swing• If a wing drops, simultaneously apply STOP

light and make a loud radio call to the winch


Winch Driver – Take Up Slack

• Take Up Slack at correct speed – slow walk• Assess 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 drops• If 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 needed

• Correct engine idle speed can ensure consistent Take Up Slack speed with most winch types


Winch Driver – All Out

• Excessive acceleration may reduce the chance of a wing drop in some situations

• BUT 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 react

• The key is prompt reaction to All Out, but to accelerate at the normal rate

• For more info on acceleration see Winch Operations presentation on this DVD


All pilots and members of the launching team can contribute to

reducing groundloop and cartwheel accidents during winch launches


Can we manage to STOP THE DROP

from 2013 onwards?

safe winch launching stop the drop! bga safe winch launching initiative

Documents

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wing runner

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