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44 FEATURE Sharing the skies – gliders Sharing the skies—gliders Pilots of powered aircraft who have watched wedge-tailed eagles effortlessly soaring may have wondered at their mastery, but glider pilots say they feel a kinship with the eagles. Both fly in the same way, by soaring on the warm rising air of thermals, meaning that both must instinctively know much more about the dynamics of the sky than the typical powered pilot. ‘Formally’, gliders, or sailplanes as they are now known, have been flying in Australia for over 60 years, although gliding began earlier in the ‘20s and ‘30s with opencockpit trainer gliders launched from hilltops. The peak association, the Gliding Federation of Australia (GFA), began in 1949, bringing together the various state and local bodies which then made up the gliding community in Australia. The GFA has a core membership of 2500 pilots, with short-term memberships catering for those wanting to give gliding a try swelling the number during summer. There are around 1200 sailplanes on the register (gliders are VH-registered). The bulk, around 1000, are conventional sailplanes, while the remaining 200-odd are powered. And because they are VHregistered aircraft, gliders are subject to the same airworthiness regime as other VH-aircraft, with regularly scheduled inspections. The GFA administers this ongoing airworthiness, with approved and certified inspectors. There are several methods of launching gliders, with the most commonly used in Australia being ground-based winch and aerotow, which uses a tug plane to take the glider to launch altitude, explains Chris Thorpe, GFA operations manager. Winch launching and aerotow each have unique characteristics. Bacchus Marsh airfield, for example, is home to three gliding clubs, and uses winches and tug planes. In winch operations, Thorpe says, ‘the glider goes up pretty quickly, at a 45-degree angle, and only takes about 30-40 seconds to get to release height (2000ft AGL).’ Since the winch cable ‘in Australia, in the main, is 3.5mm spring steel and can go up to 3000 or 4000 feet in the right conditions’, Thorpe advises pilots to check the relevant world aeronautical chart (WAC) to look for a winch symbol for the area they are planning to fly over. ‘You don’t want to be flying over an aerodrome if it is doing winch operations,’ he says. ‘Crosswind joins are especially dangerous; in any case, pilots should give the circuit a bit of margin.’ For this reason, ‘the reporting point for the airfield has been moved to the Bacchus Marsh township, so that pilots don’t fly over the aerodrome’. ‘Aerotow is fairly sedate,’ he says, but it has still some unique features powered pilots should be mindful of. The glider/ tow plane combination is not very manouverable, and the tow plane, often flying nose-high, cannot see particularly well to the front, and cannot take significant evasive action without releasing the glider. So pilots of powered aircraft should be aware of the limited capacity of a glider under tow to get out of the way – ‘it’s basically formation flying’, Thorpe adds, ‘so give the glider plenty of room, and don’t fly too close’. Pilots of powered aircraft should be aware of the distinct flight characteristics of gliders, Thorpe says. Landing, in particular, is a phase of flight that is very different for unpowered aircraft.
Flight Safety Australia Issue 87 July–August 2012 45 ‘It’s very important that powered pilots understand that gliders only have one shot at landing, so it’s not a good idea to cut in front, or exercise a perceived right over a glider that’s set up for landing. ‘Every landing we do is a forced landing,’ he says. ‘We don’t have the luxury of having another go’. ‘It’s very important that powered pilots understand that gliders only have one shot at landing, so it’s not a good idea to cut in front, or exercise a perceived right over a glider that’s set up for landing. In fairness, most powered pilots are good like that.’ A nasty little detail for IFR powered pilots to remember is that for some aerodromes (Kingaroy, Queensland, for example) the missed approach procedure directs traffic through gliding areas. This is not an issue in actual IFR conditions, obviously, but could contribute to a major fright—or worse—should an IFR pilot in training, head-down, practise a missed approach without first reading the ERSA and NOTAMs, and broadcasting conscientiously on the correct frequency. In their ceaseless quest for lift, glider flightpaths differ from those of powered aircraft. Gliders rarely fly in a straight line for more than a few minutes at most, and their airspeed also varies, as pilots seek the optimum cross-country speed. ‘We go from A to B via C, D, E, F and G (in a saw-tooth profile of descending and then climbing in thermals),’ says Thorpe. Gliders generally fly in class G and class E (non-controlled for VFR) airspace, but can be found in class A airspace at up to 35,000ft. This is legal if the glider has received block clearance from ATC, usually by prior arrangement. The world glider altitude record is 50,679ft and VNE for most gliders is about 140kt. Circuit speeds are usually between 65kt and 45kt and speeds between thermal climbs can be anywhere from 60kt to 120kt, depending on type. However, during competitions, high-performance gliders can sometimes return to the airfield at low level and at speeds of up to 150kt. A skilled glider pilot who finds a rising column of air will often exploit the glider’s efficient wings to stay inside it. Gliders in thermals will often turn much more steeply than most powered aircraft. Banks of 45 degrees are common in this situation, with 60-degree banks not unknown. Rates of climb in thermals can exceed 1000fpm on a hot summer day. On a day with cumulus clouds, thermalling gliders will be found close to the cloud base, their white wings blending all too effectively with the grey cloudbase. Three frequencies have been allocated for gliders to use. They are 122.5, 122.7 and 122.9. Gliders flying in a common traffic advisory frequency (CTAF) area will use the CTAF frequency, but they have an exemption from monitoring area frequency, as gliders flying closely together cross-country and during competitions will usually communicate on one of the allocated glider frequencies. ‘We fly the same radio procedures as everybody else, except for that exemption,’ says Thorpe. Gliders are not currently required to carry transponders, but many use FLARM, a collision warning system similar in principle to ADS-B that provides proximity advice for gliders and tugs so equipped. FLARM, short for flight alarm, is an off-the shelf, low-cost proximity-warning system suited to relatively slow-moving aircraft such as gliders. FLARM does not communicate with other automatic dependent surveillance systems, but this function is being considered. Sample NOTAM for Bacchus Marsh 1. Gliding OPS HJ - Aerotow and winch launched. Gliders and tugs normally operate inside and below standard 1000ft circuit. 2. All circuits left-hand. Unforseen circumstances may occasionally force a glider to fly a right-hand circuit. 3. Gliders and tugs operate from righthand side of RWY short of displaced THR. Other ACFT must not make low/ shallow approaches and must land beyond displaced THR. 4. When gliding OPS in progress the duty RWY is the RWY in use by the gliding operation. All TKOFs to commence from the displaced THR. 5. If wind is BLW 5KT and VRBL, RWY 19 or 27 must be used by all ACFT. WInd ABV 5KT, operate on the most into wind RWY. 6. Overflying the AD is discouraged. If operationally necessary, overfly at 2,000FT AGL (2,500FT AMSL). 7. When inbound it is suggested ACFT track via and call on the CTAF at one of the following points - Melton Reservoir, Merrimu Reservoir, Pykes Creek Reservoir or Mt. Anakie.
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Page 3 and 4: CONTENTS Issue 87 | July-August 201
Page 5 and 6: Flight Safety Australia Issue 87 Ju
Page 11 and 12: ‘They’re being used now,’ she
Page 19 and 20: Check your flight notifications The
Page 21 and 22: Australian accidents/incidents 01 A
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Page 55 and 56: If in doubt, don’t take-off ATSB
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Page 59 and 60: REPCON BRIEFS Australia’s volunta
Page 73 and 74: AUSTRALIAN Flight Safety Australia
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