Winching Operations

1. BGA Safe Winch Launching Initiative WinchingOperations

2. Review • The Safe Winching Campaign has contributed to an improved accident record since 2006

3. Review • Key Winching Operations campaigns so far: • Safe cable speed • Excessive acceleration

4. Review • Key Winching Operations campaigns so far: • Safe cable speed • Excessive acceleration

5. Safe Cable Speed • “Maintain shallow climb until adequate speed (1.5Vs) with continuing acceleration” • If winch CAN’T achieve acceleration through 1.5Vs we have a problem! • Need a Winch cable speed spec to back-up trained pilot technique • For details see winchcablespeed.pdf on this DVD

6. Recommended Cable Speed The above shows that all winches should be capable of at least 60kt cable speed in order to launch ALMOST ALL glider types safely in NORMAL conditions 65kt+ cable speed is beneficial if launching high wing-loading gliders (eg turbo/water ballast) or in worst-case conditions (hot day, light tailwind) <60kt winches require pilots to take extra care due to reduced energy margins during rotation in nil headwind conditions

7. Low Speed Winches • Before campaign, over 10 winches in use unable to achieve safe cable speed • Sometimes as low as 50kt max speed • Regular abandoned launches • Low energy = Difficult recovery • Contributory factor in accident record?

8. Solutions Used • Increase Tost winch rev limit • Fit larger diameter drums to Tost winch • Change gearing of homebuild diesel • Buy used winch from another club • Winch rebuilt including cable speed upgrade

9. Symptoms of <60kt Winch • Speed “hovers” at <1.5Vs until you climb • Abandoned launches in zero headwind • K13s etc OK but glass pilots not happy • Winch drivers using max throttle/revs but feel they still need more If you have these symptoms, the BGA Winching Advisor can assist with winch assessment

10. Examples of <60kt Winches • 6cyl diesel Supacat55kt • Tost IV with 4500rpm rev limiter 56kt • Wild in 2nd gear with max 5000rpm 50kt • Home-made winch ?? • Old diesel winch ??

11. <60kt Winch Mitigation • If occasional tailwind, WAIT! • Limit types launched if nil headwind • Careful rotation and speed monitoring • Winch driver use max revs if needed • Take great care with visiting pilots not used to low speed winches

12. Review • Key Winching Operations campaigns so far: • Safe cable speed • Excessive acceleration

13. Excessive Acceleration • Excessive winch acceleration can cause gliders to pitch up rapidly regardless of stick position • Synthetic 8-10mm rope, which stretches during acceleration, can accentuate this • Good winch driver technique can minimise this problem

14. Excessive Acceleration Diagram courtesy of Steve Longland

15. Problems With Rapid Pitch-Up - 1 • Reduced margin to stall speed!

16. Problems With Rapid Pitch-Up - 2 • Glider height and speed are low = low energy • Glider is nose-high = rapid speed decay • EVEN WITH A PERFECTLY FLOWN RECOVERY, A SAFE OUTCOME FROM A LOW LAUNCH FAILURE MAY NOT BE POSSIBLE IN THIS SITUATION. EVEN THE MOST COMPETENT PILOT CAN BE PUT IN THIS SITUATION BY BAD WINCH DRIVING • Think about it!

17. Solutions – Winch Drivers • Ensure type to be launched is known • Smooth and progressive throttle opening • 3sec acceleration with Skylaunch or similar • Extra care with lightweight or stretchy ropes • Engine sound assists acceleration judgement • Ask for feedback from pilots • Read “Don’t force your mate’s crate to rotate” in S&G April/May 2010

18. NEW CAMPAIGN Fouling the Cable

19. Fouling the Cable • Winch accident and incident reports 2006-2011 reviewed for any trends • 2011 had 6 events of cables fouling gliders; same as 2008/9/10 together • Clearly this needs understanding and addressing, as worst-case cable fouling accidents can be fatal

20. What Can Happen? • Low launch failure - Parachute inflates - Cable hits or becomes tangled with glider • Weak link break – Strop recoils into glider • Take Up Slack jerk – Strop around wheel • Landing near a moving cable/parachute • Crossed cables • Winch driver launches glider or moves cable when gliders/people on cable run

21. Safer Launch Failure Training

22. Instructors – Simulated Cable Breaks • Low launch failure training by pulling the release carries a high risk of fouling the cable • ULTRA-LOW launch failures (<50’) are DEMO ONLY and are simulated by winch driver “power chop” • BUT what about other height launch failures? • What are the pros and cons?

23. Instructors – Power Chops • A “power chop” is an option at all heights • Less chance of glider/cable conflict. The parachute falls away dead, behind the glider • BUT instructor not fully in control of timing: • Tricky to achieve requested height/position • Committed to receiving the failure. What if pupil over-rotates or another hazard develops?

24. Instructors – Bung Pulling! • Fully in control of height/position for failure • If not safe to pull it, not committed – can delay • BUT Parachute WILL initially inflate, until winch driver reacts – Possible hazard for landing ahead • If “pulling the bung” for a low launch failure, brief winch driver to stop immediately and be ready to avoid the parachute!

25. Comparison Diagram • Typical sequences for both methods of launch failure training are shown in the next diagram • In both cases, the failure occurs in position 2

26. typical locations of glider and parachute after recovery has commenced Diagram courtesy of Steve Longland

27. Clearly, the chance of the glider contacting the cable or parachute is reduced if the “power chop” method is used for training low failures

28. Instructors – Decisions! • Always consider both methods for launch failures • Medium & High failures not normally a problem • Low/Land-ahead failures require consideration • Height? Cable angle? Wind? Landing options? Parachute reaction? Winch braking distance? Pupil experience? Instructor experience? • Choose the best option for each exercise • Be confident with both methods

29. Recommendation • Purely from the point of view of minimising cable fouling accidents, power chops are recommended for launch failure training <200’ • If other factors outweigh this recommendation and you wish to pull the bung at <200’, then brief the winch driver and avoid the parachute • Always weigh up the risks and benefits associated with each launch failure method at different heights and positions

30. Still not convinced that power chops improve parachute separation? Watch this video....

31. Click on picture to play. Click outside picture to advance to next slide

32. The parachute drops safely below and behind the glider, and doesn’t inflate until well clear. Bloggs would have to try very hard to hit it!

33. Real Launch Failures • Unfortunately, we can’t arrange for real launch failures <200’ to all be power chops! The power may fail gradually or be inadequate from the start, or any part of the cable system may fail • At low level, these scenarios can result in the parachute inflating near the glider • Real launch failures at low level can be caused by errors from the ground team. Be “switched on” in the winch and at the launch point

34. Common Factors in Cable Fouling Accidents

35. Common Factors – Fouling Cable • No STOP signal, delayed or not spotted • Parachute/strop arrangement poor • Slow initial launch – abandoned • Cable towout not straight • Parachute not untwisted before launch • Incorrect winch driver reaction to problem

36. Common Factors – Fouling Cable • No STOP signal, delayed or not spotted • Parachute/strop arrangement poor • Slow initial launch – abandoned • Cable towout not straight • Parachute not untwisted before launch • Incorrect winch driver reaction to problem

37. Possible Reasons for STOP After All-Out • Wing Drop • Cable fouls glider • Cable, weak link, parachute, shackle failure • Abandoned launch • Uncommanded cable release inc. hook failure! • Crossed cables – another cable moves • Low simulated cable break • Conflict with landing or overflying aircraft

38. STOP! - Winch Drivers • Keep watching light signals while accelerating, until you get a good view of the airborne glider • Always be ready for a Take Up Slack or All Out to change to STOP and ensure radio is audible • SKYLAUNCH actions: CLOSE throttle instantly, PULL Drive lever back to Neutral, BRAKE HARD until drum stopped • Watch glider and assess situation – Consider Guillotine, Drum Neutral, Engine off etc • What are the STOP actions for your winch?

39. STOP! - Launch Signaller • Be ready to change signal to STOP! at any time • Continue to monitor launch after All Out • With lights, understand that winch driver will be focussing on glider soon after All Out • Always back up a STOP light with a loud radio call to ensure prompt response from winch • Preferable to have radios with good aerials, decent battery life and a clear channel

40. Common Factors – Fouling Cable • No STOP signal, delayed or not spotted • Parachute/strop arrangement poor • Slow initial launch – abandoned • Cable towout not straight • Parachute not untwisted before launch • Incorrect winch driver reaction to problem

41. Recommended Cable Setup • Tost rings or equivalent • “Strop” 3m (+/- 0.5m) • Weak link in holder, with slot towards glider • “Trace” 17m (minimum 12m, no maximum) • Parachute – minimum usable size for site • Max chute open diameter 1.5m steel/1.2m synthetic • Swivel if needed, then winch cable • Reduce metalwork where possible • System has parachute at least 15m from glider

42. Diagram courtesy of Steve Longland

43. Recommended Cable Material • For 3m “Strop” from Tost rings to weak link…. • Rope (eg polypropylene – min stretch) 14+mm diameter, ideally encased in hose or pipe • 4.5-6mm steel cable encased in hose or pipe • 5mm+ Dyneema encased in hose or pipe • Hose/pipe in good condition – no bare cable! • Minimum diameter 12.5mm (½”) garden hose • Same materials for 17m “Trace” from weak link to parachute, but if using 14+mm rope, hose/pipe not needed

44. Advantages of Recommended Setup • Weak link and any bare cable clear of nosewheel/skid – less chance of hangup • Weak link break/recoil - Less stored energy in short 3m strop than if weak link at parachute • Diameter/material of strop less likely to catch in mainwheel during overrun • Distance between parachute and glider allows time to react and avoids distraction

45. Example Setup

46. What Can Go Wrong – An Example • Cable setup with only 5m from glider to ‘chute • 15kt headwind • Cable break before takeoff, at around 30-40kts • ‘Chute flew back over the canopies obscuring the pilots’ view, then wrapped around cockpit • Main wheel jammed and instructor trapped • If the glider had been airborne, would have been a tricky landing with view obscured • Club now uses recommended setup!

48. Common Factors – Fouling Cable • No STOP signal, delayed or not spotted • Parachute/strop arrangement poor • Slow initial launch – abandoned • Cable towout not straight • Parachute not untwisted before launch • Incorrect winch driver reaction to problem

49. Slow Initial Launch Incidents • Typically launching light gliders in a headwind • Parachute inflates in front of glider due to low tension OR pilot releasing due to low speed • Both caused by winch driver providing insufficient speed for glider to rotate safely • ½ of incidents = Skylaunch with throttle stops • ½ of incidents = other types without stops

50. Skylaunch: Headwind > 10kts • Throttle stop setting may be ideal once glider in full climb, but may be insufficient to give normal acceleration through wind gradient • Throttle stop is JUST A GUIDE to approx power • Always be ready to adjust throttle as needed • LISTEN TO ENGINE - smoothly increase throttle if engine sounds laboured/doesn’t accelerate • WATCH GLIDER - smoothly increase throttle if glider doesn’t enter full climb normally