Safe Winch Launching WINCHING OPERATIONS BGA Safe Winch Launching Initiative.
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Transcript of Safe Winch Launching WINCHING OPERATIONS BGA Safe Winch Launching Initiative.
Safe Winch Launching
WINCHING OPERATIONS
BGA Safe Winch Launching Initiative
Safe Winch Launching
Review
• The Safe Winching Campaign has contributed to an improved accident record since 2006
Fatal/serious injury winch accidents
6 years 2006-2011 4 (none in 2010 or 2011)
6 years 2000-2005 18
Average 6 year period 1976-2005 18
Safe Winch Launching
Review
• Key Winching Operations campaigns so far:– Safe cable speed– Excessive acceleration
Safe Winch Launching
Review
• Key Winching Operations campaigns so far:– Safe cable speed– Excessive acceleration
Safe Winch Launching
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
Safe Winch Launching
Recommended Cable Speed
Glider Type 1.5xVs (1g) Min. Winch Cable Speed (eg nil headwind)
Rec. Winch Cable Speed (eg for hot day/tailwind)
Ka6/Ka8 45kt 50kt 55kt
Ka13/light single 50kt 55kt 60kt
K21/standard class single 55kt 60kt 65kt
Turbo/50l water 60kt 65kt 70kt
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
Safe Winch Launching
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?
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
Examples of <60kt Winches
• 6cyl diesel Supacat 55kt• Tost IV with 4500rpm rev limiter 56kt• Wild in 2nd gear with max 5000rpm 50kt• Home-made winch ??• Old diesel winch ??
Safe Winch Launching
<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
Safe Winch Launching
Review
• Key Winching Operations campaigns so far:– Safe cable speed– Excessive acceleration
Safe Winch Launching
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
Safe Winch Launching
Excessive Acceleration
Diagram courtesy of Steve Longland
Safe Winch Launching
Problems With Rapid Pitch-Up - 1
• Reduced margin to stall speed!
Safe Winch Launching
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!
Safe Winch Launching
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
Safe Winch Launching
NEW CAMPAIGN
Fouling the Cable
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
SAFER LAUNCH FAILURE TRAINING
Safe Winch Launching
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?
Safe Winch Launching
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?
Safe Winch Launching
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!
Safe Winch Launching
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
Safe Winch Launching
typical locations of glider and parachute after recovery has commenced
Diagram courtesy of Steve Longland
Safe Winch Launching
• Clearly, the chance of the glider contacting the cable or parachute is reduced if the “power chop” method is used for training low failures
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
WATCH THIS VIDEO....
Still not convinced that power chops improve parachute separation?
Safe Winch Launching
Click on picture to play.Click outside picture to advance to next slide
Safe Winch Launching
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!
Safe Winch Launching
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
Safe Winch Launching
COMMON FACTORS IN CABLE FOULING ACCIDENTS
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
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?
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch LaunchingDiagram courtesy of Steve Longland
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
Example Setup
Safe Winch Launching
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!
Safe Winch Launching
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
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
Safe Winch Launching
Skylaunch: >10kt Headwind Option 1
• Underestimate Headwind by 1 notch/5kts• Eg In 20kt headwind select 15kt setting• Accelerate smoothly to throttle stop • Watch glider and listen to engine for feedback
– adjust power if required• Be ready to smoothly reduce power once
glider is through wind gradient• Rest of launch normal
Safe Winch Launching
Skylaunch: >10kt Headwind Option 2
• Select correct headwind • Accelerate smoothly to throttle stop then
slightly beyond (5-10mm normally sufficient)• Watch glider and listen to engine for feedback
– adjust power if required• Be ready to smoothly reduce power once
glider is through wind gradient• Rest of launch normal
Safe Winch Launching
Skylaunch Throttle Stops
• Useful guide and training aid - consistency• Work well in light winds, but more judgement
needed in stronger headwinds• Drivers who can only “launch by numbers” are
not fully trained winch drivers!• Drivers should have sufficient judgement to be
able to adjust power as required
Safe Winch Launching
Other Winch Types• Same principle applies to most winch types• In a strong headwind, the lower power-setting
required in the full climb may not be sufficient for the glider to rotate safely
• Need to accelerate the glider through the wind gradient first, then adjust power in full climb
• If glider doesn’t rotate normally or engine sounds laboured, smoothly increase throttle
• Ask your winchmaster for advice specific to your type of winch
Safe Winch Launching
Diagram of Headwind Launch
• The following diagram illustrates option 2 for driving a Skylaunch in >10kt Headwind
• Option 2 is selecting the correct headwind, but initially accelerating slightly beyond the throttle stop for the first part of the launch
• The general principle applies to most winches• Don’t forget that the windsock indicates the
wind strength at 10-15ft above the ground. Glider headwind below this height is likely to be less than indicated by the windsock
Safe Winch Launching
Diagram courtesy of Steve Longland
Safe Winch Launching
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
Safe Winch Launching
Crossed Cables - Causes
• Towout not straight• Cables not separated at launch point• Glider queue too close to cables• Winch driver launches with previously used
cable too close to the cable in use. Has to abandon launch when cables tangle
• Towout driver hooks cables up incorrectly• Winch driver moves winch with multiple
cables out on field!
Safe Winch Launching
Wonky Towout?
• Drive full length and ensure separation• If clear, launch cable inside of bow first• If doubt, wind inside cable in - launch 2nd only• DO NOT be pressured into launching• Rebrief/retrain/replace towout driver!
• If using a single cable in a large bow (eg winter ops), ensure no landed gliders, people or vehicles are within the bow before launching!
Safe Winch Launching
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
Safe Winch Launching
Parachute Not Untwisted
• Any twisted part of the cable system can create a jerk during acceleration and rotation
• This can be enough to briefly open parachute, or alarm the pilot sufficiently for him to lower the nose or release at low level
• To avoid these incidents ALWAYS ensure cable system untwisted before hooking on
Safe Winch Launching
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
Safe Winch Launching
Winch Driver Reaction
• With low launch failures, glider/cable separation CAN’T be guaranteed – CABLE MUST BE STOPPED IMMEDIATELY
• 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
Safe Winch Launching
REVIEW
Safe Winch Launching
Cable Fouling Review
• Power chop for ultra-low launch failure demo• Power chops recommended for failures <200’• Think about best method each time• Improve STOP communication and procedures• Use recommended cable setup• Use sufficient throttle for rotation in headwind• Straight cable towouts and untwisted ‘chutes• STOP drum immediately with low failures• Train winch drivers fully – not “by numbers”
Safe Winch Launching
Summary
• Gliders being fouled by winch cables is a threat
• There is plenty we can do to reduce the risk• If everyone is “switched on” we can all help• Target is to revert to downward trend of “hit
cable” incidents and accidents from 2013 on• Keep reporting winch accidents/incidents to
help our work to understand and reduce them• Thank you