Tug Pilot Manual

2005 Electronic Edition


Contents

 

1. GENERAL

2. ROBIN DR400 and DR300 OPERATING NOTES

3. SUPER CUB OPERATING NOTES

4. THE LYCOMING O-360 SERIES ENGINE

  • 4.1 GENERAL
  • 4.2 CYLINDERS
  • 4.3 VALVE OPERATING MECHANISM
  • 4.4 CRANKSHAFT
  • 4.5 CRANKCASE
  • 4.6 OIL SUMP
  • 4.7 CONNECTING RODS
  • 4.8 PISTONS
  • 4.9 ACCESSORY HOUSING
  • 4.10 GEARS
  • 4.11 COOLING SYSTEM
  • 4.12 LUBRICATION SYSTEM
  • 4.13 INDUCTION SYSTEM
  • 4.14 IGNITION SYSTEM

APPENDICES (Not yet included)

  • TUG PILOTS - Details now within main site >>>>
  • APPROVED AIRFIELD LIST
  • LOCAL AIRSPACE
  • LIGHT AIRCRAFT MAINTENANCE SCHEDULE
  • AIR NAVIGATION ORDER (extract)

1. GENERAL

1.1     INTRODUCTION

It is important to remember that as a Tug Pilot you have considerable responsibility to the London Gliding Club.  Aero-towing is an expensive and noisy operation.  Both factors have a bearing on the very existence of the gliding club and it is essential, therefore, that Aero-towing be carried out efficiently and thoughtfully, particularly with regard to our neighbours.

Aero-towing should be carried out in accordance with the following procedures and in conjunction with the London Gliding Club’s Operations manual and Club Rules.  Within these constraints the glider pilot’s requirements should be accommodated as far as possible.

1.2     APPROVAL TO FLY TUG AIRCRAFT

Initial approval to fly tug aircraft will be issued by the Chief Tug Pilot (CTP), after discussion and approval from the CFI and Deputy Chief Tug Pilot (DCTP). See Pilot Details for current list of Tug Pilots.

Each Pilot will be checked annually and his approval reviewed.  The flying check will be done by the Chief Tug Pilot, DCTP or a Check Pilot.

Specific authorisation and in some cases differences training will be required for the following;

1.    Any flight away from Dunstable.

2.       Retrieves from fields.

3.    Retrieves from airfields. See section 1.22 and Approved Airfield list.

3.    Dual aero-tows.

4.    Aero-towing with the Super Cub. Current Pilots can be found under Pilot Information.

5.    Aero-towing with G-LGCA. Current Pilots can be found under Pilot Information.

5.    Aero-towing with any other aircraft that may be used from time to time by the London Gliding Club.

6.    Aero-towing from the East run (See 1.8.5).

These authorisations will be issued by the CTP.

A flying check/refresher with the CTP or DCTP is necessary if no tug flying has been done for 3 months or more.

An approved tug pilot may not fly if his medical or licence has lapsed. The onus for keeping medicals current rests with the pilot. On renewal, the new expiry date should be passed to the CTP. This information is held under Pilot Details.


1.3     LICENCES and MEMBERSHIP

Each tug pilot must be a full flying member of the London Gliding Club. The current list can be found under Pilot Details.

Each tug pilot must hold a valid Pilot’s Licence. This must include the following;

1.  A valid medical certificate.

2.  A valid Certificate of Revalidation or a PPL issued within the last 12 months. The Certificate of Revalidation is valid for 24 months, the expiry date will be specified in the Licence.

The Certificate of Revalidation contained in the licence must be signed and be current for “SE Piston(land)” aircraft. Any JAA Type or Class Rating Examiner (TRE or CRE) may sign the certificate, once he is satisfied that 12 hours P1 have been completed on any SE piston aircraft during the preceding 12 months. AND;

He has completed at least 1 hour’s flying with a Class Rating Instructor (CRI) in the preceding 12 months. The flight is essentially a general handling and aero-tow refresher, it follows a format determined by the BGA. Revalidations are lodged with the CAA for general licence usage.

JAR reference and an example of a completed FCL150CJAR form in the licence. Note that for holders a TMG endorsement, this can be combined with the SEP revalidation. For those with SLMG, it can revalidated on the "National" page or by stamp in the logbook, but does require standalone recency compliance.

Completion of any Licence Skill Test in the preceding 12 months can be substituted for the 1 hour Flight Refresher at the discretion of the Class Rating Examiner.

See Pilot Details for current CAA/JAR Authorised Examiners.

1.4     ENGINE HANDLING

All LGC aircraft are fitted with 180HP Lycoming O-360 engines. Section 4 gives full details of this engine.

Glider towing is very hard on engines, due to alternate use of high and low power settings.  Cylinder head cracking can happen when rapid changes (temperature “shocks”) or differential changes in temperature occur in an engine.  With our operation this is on take-off when applying full power and most critically at the release point of the launch, when power reduction is aggravated by an increase in airspeed and consequent increase in ram air cooling. Standard operating procedures have been devised to minimise thermal shocks, and manage the engine’s temperature profile.

Specific engine handling procedures are listed under the relevant “Robin” and “Super Cub” operating notes in sections 2 and 3 of this manual.

 

1.5     NOISE ABATEMENT

Continual towing or descent over the same area causes considerable nuisance and irritation to our neighbours.  Whilst we can do little to reduce the actual noise produced, we can spread the load by thoughtful and varied tow-out patterns.  It is variation, therefore, that forms the basis for our noise abatement procedures.  The following general points should be considered, along with specific procedures as laid down in section 1.8 Launch Points.

1.  Avoid over-flying all houses just after take-off (See 1.8 Launch Points).

2.  Fly around or downwind of Edlesborough, Eaton Bray and Totternhoe until at least 1500’ agl. Do not fly over Dunstable below 1500’ agl. Refer to Figure 1.


 
Figure 1

3.  Use the airspace immediately overhead the London Gliding Club (See 1.7 Local airspace).

4.  Make full use of all airspace available to us within the Luton SRZ (See 1.7 Local Airspace).

5.  It is not always necessary to drop upwind, a tow made for the most part downwind of the site and then terminating overhead or slightly upwind of the site, can sometimes be used.

6.  Remember that when turning, the focal point of your turn (the lower wing will be pointing at it) will be subjected to a concentration of tug noise.

7.  A soaring pilot may be happy to be towed directly away from the site, this should be done when the opportunity arises.

8.  Evenings and Sundays are particularly sensitive periods.

Remember that the noise of a descending tug with a relatively high power setting can be equally annoying, apply the same techniques in descent as well. Also, try and make your descent route different from the tow out route. Do not descend below 500 feet until entering base leg.

1.6     OPERATIONAL REQUIREMENTS

1.6.1   It is the tug pilots responsibility after full consultation with the instructor in charge, to terminate aero-tow operations when darkness approaches.  Do not launch a glider after sunset + 10 minutes.  Resist all forms of persuasion to launch in these circumstances.  In order to establish the precise time sunset tables are reproduced on the front cover of each Tech. log and in Sunset Table.  Advise the instructor in charge of this time a little in advance.

1.6.2   It is the tug pilot’s responsibility to terminate aero-tow operations if visibility, wind strength or cloud base make operations hazardous. Some of these limits will depend on the type of tug in use.

1.6.3   Before every take-off, check that the winch launch is not taking place or about to take place (see also 1.9 Radio Procedures).  If it is, delay launch until the cable is back on the ground. Do not take off across the winch cables.

1.6.4   If non-radio; do not take off unless a forward signaller is in position.  In exceptional circumstances (e.g. organised evening flying), a forward signaller may be dispensed with if signalling is specifically arranged to be via the tug’s rear view mirror.

1.6.5   Before take-off note on the Tug Log Card the glider, name of pilot to be charged and the take-off time.  Subsequently record the exact aero-tow release height (to the nearest 100’).  These cards are essential for rendering launch charges to Club members and must be legible and accurate.  For example a release at 2100 feet should be recorded as such and not as 2000 feet.

1.6.6   Cloud flying with a glider on tow shall not be undertaken without prior arrangement with the glider pilot and then strictly at the tug pilot’s discretion.

1.6.7   Ensure adequate clearance of the tow rope from the ground when approaching to land, this is particularly important on the East and South West runs.  Do not overfly people, aircraft or vehicles prior to landing.

1.6.8   Do not land tug aircraft on hangar ridge or on the new ground to the South East of the trailer racks.

1.6.9   Passenger carrying is NOT allowed whilst Aero-towing. Exceptions to this rule must have specific authorisation from the CFI, CTP or DCTP.

1.6.10 ALL flights away from Dunstable require authorisation from the CFI, CTP or DCTP. 

1.6.11 Anti-collision lights, where fitted, should be on whenever the engine is running.


1.7     LOCAL AIRSPACE

General

The airspace around Dunstable is complex and subject to change. A thorough working knowledge of the local geography and position of airspace boundaries is essential for all tug pilots. Tug pilots can be expected to be checked regularly on their knowledge of this. The Local Airspace section of the website shows the local airspace and it’s restrictions. It also shows the airspace in which aero-towing can take place when Luton are operating their runway 08. This information is subject to change from time to time and will be shown on the latest CAA 1:500,000 Southern England chart and/or the Letter of Agreement we have with LATCC.

1.7.1   All tug pilots must have an Airspace Rating for operations in and around the London Gliding Club.

1.7.2   All tug pilots must be familiar with the aero-towing concessions available when Luton are using 08, and make appropriate use of them.

1.7.3   All tug pilots must be familiar with the boundary between the 3500' based CTA and the 4500' based CTA, in order to take gliders requiring 4000' tows legally and efficiently to the an optimum position below the 4500' CTA. Diagrams and key features to achieve this are included in the Local Airspace part of this website.

1.7.4   Aero-tows should also make use of 26 airspace when Luton are using 26, but locally the Status is 08. Landing direction at Luton is constantly promulgated on Luton ATIS 120.57. This should monitored and confirmed before entering the 26 area.

1.7.5   Occasionally glider pilots will request an aero-tow above 4000'. This can be done towards the North West under the Daventry CTA. The tug pilot must know these boundaries before agreeing to the tow.



1.8     LAUNCH POINTS

1.8.1     General

Each take-off and landing direction at Dunstable presents the Tug pilot with particular problems and specific procedures to follow. Listed below are notes and diagrams relating to each of the take-off and landing directions.

There is considerable risk to people and gliders when an engine is running. Therefore, Tugs should always be parked and taxiied well away from the Launch point area. As a rule, a Tug should not approach closer than 10 metres to a glider awaiting launch, normally a greater and safer distance can be achieved.

1.8.2     South West Run (Figure 2 and 3)

Launch position;   Gliders must be parked as shown on Figure 2. There is enough room for two K21’s side by side, providing the Control tower is correctly positioned.

Take-off;                The take-off path must be kept within the area shown on Figure 2, That is between the 12 metre wide sterile area towards the gulley and the central cable pull-back line. If necessary the glider must repositioned to facilitate a safe take-off within the boundaries described. The surface on the Clubhouse side of the cables is too rough and must not be used for Take-offs.

                          

                                                Figure 2

Routing;             There are two early route options, as shown on Figure 3, either route between the pig farm and the Tring road (A) or between the pig farm and the hill (B). The second option (B) requires adequate climb performance in order to comfortably clear the power lines. Don’t overfly the winch. Be aware that gliders or vehicles on the North East run landing area may not be visible from the launch point.

Landing;            The approach should always be steep enough to avoid any possibility of the rope fouling the public footpaths on the airfield boundary. If the surface of the downslope of Hangar ridge is kept in view at all times during the approach, then an adequate margin will be achieved. Always land on the upslope beyond the dip. Note that the upslope is steeper towards the Tring Road. A few extra knots may be useful to counter the effects of the upslope.

Beware of curlover on short finals and in the dip in strong wind conditions.

Figure 3;  The South West run

Landing long or on the East run are alternatives for a crowded landing area.

If possible taxi back along the sterile area shown on Figure 2. If returning via Hangar ridge, try and anticipate power requirements for climbing the slope in order to avoid high static power settings and in any case avoid the very steep slope near the launch point.

Parking;             Tugs should be parked in line with the edge of the gulley and well forward of the launch point area as shown in Figure 2.

Grid position;    If a Grid is formed on this run it will normally be on the hill side of Hangar ridge. Tugs will position about 2/3 of the way up Hangar ridge and take-off downhill. Exercise care with power and brakes in these circumstances. Parking of tugs for this launch should be on the hill side of the upslope and at 90° to the slope or slightly uphill in the case of the Super Cub.

              

1.8.3     North East run (Figure 4)

Launch position;   This should be set up to the left of the Control Tower and consist of up to two gliders abreast. Further gliders should be queued behind or to the left. If the gliders are placed too far from the Control Tower the take-off path will be compromised.

It is also important that the Control Tower is positioned correctly to permit full utilisation of the tug take-off area. This is approximately 50m from the end of the hedge towards the hill. If necessary reposition correctly before commencing operations.

Take-off;            Before commencing a take-off a midfield batman (M) must be in position and confirm “clear over the brow”. The normal take-off direction will be to the right of the bushes whilst keeping to the Tring road side of the trailer racks. Ensure you have enough clearance from the bushes to accommodate an out of position glider or large wingspan glider, this is particularly important with a crosswind from the right. This route will take the aero-tow over the Club entrance. Ensure that the ground run is contained within the recently prepared take-off area.

Routing;             The initial route provides two options; Straight out to the left of “The Avenue” (B) or a left turn downwind (A - between Totternhoe and the Tring Road) to return overhead later. The first and simplest option (B), is particularly noise sensitive and should be used sparingly. Preference for this route should be given to training gliders where possible. Try and keep the ratio route A to route B to 2:1 or better.

Landing;            Landings should be made to the right of the launch point. This will mean crossing the winch cables when taxiing back. Ensure that you cross well ahead of the winch launch point and cross at 90°, continue on this heading until the tow rope has definitely cleared the cables without snagging before turning towards the launch point. Exercise extreme care. Use the radio to advise if required. Alternative for landing is to the left of the aero-tow launch point. This option requires a high approach to keep the tow rope from snagging the fence on the airfield boundary and an inevitable long landing.

Beware of downdrafts on short finals in strong wind conditions.

Figure 4; The North East run

Parking;            Tugs should be parked well away from gliders and into the Western corner of the airfield.

Grid Position;   If a large grid is required it will have to cover the area of the normal winch and aero-tow launch points combined. A smaller grid should be two gliders wide as for normal operations.

1.8.4     West run (Figure 5 and 6)

Launch position;   Normally gliders will be two abreast to the left of the Control vehicle.

Take-off;               This take-off run is particularly noise sensitive and the direct overflying of the houses on the Tring road must be avoided at all times. This then gives 3 alternative take-off paths as shown on Figure 6. The most Northerly (A) goes very close to the winch and special care must be made to co-ordinate with the winch launch point. The middle option (B) keeps just to SW edge of the hedge line. The Southerly option (C) has a bit more space but goes very close to a riding school, try and avoid their training arena as well as the buildings (marked RS on Figure 6).

There is a tendency for gliders to align themselves parallel to the winch cables, which implies taking off on route A. It is important that we cycle through the various take-off routes and this may mean realigning the glider. Some gliders will easily re-align themselves on the take-off run if the tug is properly positioned (see Figure 5). However, heavy tailed gliders cannot easily do this and must be realigned before take-off. These include ASH25, ASW22, DG500, Nimbus and similar types.

                       

              

Figure 5

Routing;             On route A, a 30° turn to the right must be made soon after take-off, in order to avoid over-flying any of the Wellhead houses. This often means overflying the winch. Then the preferred turn direction is to the South (A1). If a right turn is made, it will take the aero-tow close to the noise sensitive Western edge of Dunstable. This option should therefore be rationed left turnout (A1) to right turnout (A2) in the ratio 2:1 or better.

Routes B and C require flying straight ahead on the appropriate line until passing the Wellhead houses when a left turn should be made.

Figure 6; The West run

Landing;         Landings as for take-off are not possible, although some gliders can be expected to do this. If a left hand circuit is in progress, then the approach and landing should be into the North East glider landing area and flown as if the North East run were in operation (marked LH on Figure 6). The final landing direction may be angled into wind if necessary. In this case the Tug must be kept on the airfield side of the hedge line (marked H on Figure 6).

Care should be taken to avoid any low steeply banked turns which could be affected by wind gradient effects.

If landing cross-wind in front of the launch point, often the best option, maintain a good distance forward of the launch point and ensure a clear path is available in front of you, to facilitate an overrun or a go-around.

If a right hand circuit is in operation, then land as for the South West run (shown RH on diagram 6) and take care when crossing the winch cables.

Grid Position;            There are few problems with locating a Grid on this run, however, the take-off routes should be maintained.

1.8.5     East run (Figure 7)

Aero-tow operations from the East run can be extremely hazardous due to curl over and the requirement to turn immediately after take-off. Therefore all other take-off options must take preference. Discussion with the duty Instructor may be required. If a decision to launch Easterly is made, then only the Super Cub should be used because of its superior field performance. However it’s reduced crosswind capability may be restrictive, only 10kts crosswind component is permitted. If a crosswind is present do a "Flaps up" take-off, this technique is desrcibed under Super Cub operating procedures 3.7. Launching heavy gliders will compromise safety margins, therefore, the following gliders will not be permitted launches from the East run; ASH-25, ASW-22, DG500, DG505, Glasflugel 604, Janus, Nimbus 3, Nimbus 4 or similar types and ALL water-ballasted gliders

It should be noted that Tug Pilots must be specifically cleared to operate from the East run.

Launch position;   The launch point for the winch should be established on the edge of the new ground with two lines. A third line, immediately to the right, should be used for the aero-tows.

Take-off;                Angle the take-off run as much as possible to the South West. It is possible that some of the take-off path will be obscured and a mid-field bat may be required. When airborne and accelerating commence a shallow banked turn away from the hill. In most cases this will permit a flight path between the pig farm and the Tring road. The air is likely to be very turbulent, especially in the area marked with x’s (Figure 7), this may give the glider control problems and in turn compromise your position. Be extra vigilant and don’t hesitate to use the glider release.

Routing;             Once past the Tring road a left turn back towards the Club (A) or the hill (B) may be made. Route B is the preferred option and minimises noise nuisance, but do keep within our Airspace, the boundary of which is detailed under Local Airspace. The landing direction at Luton will almost probably be 08. Remember to keep above 1500’ when over Dunstable.

Figure 7; The East run

Landing;         The normal landing area is to the right of the bushes and towards the hill. A steepish approach will be necessary to ensure clearance of the tow rope over the power lines (marked PP) situated along the Tring road. Landings in front of the launch point may only be made when there is no winch operation.

Beware of downdrafts on short finals in strong wind conditions.

Grid Position;            It is not feasible to Grid on this run.


1.9     AIRSPEED INDICATORS

Each tug is fitted with an Airspeed Indicator calibrated in knots. The instrument carries the conventional coloured arcs. That is;-

Green Arc -  Clean/Max manoeuvre range

White Arc  -  Flap operating range

Yellow Arc -  Caution range

Red line  -     VNE.

In addition two further markers have been added to improve glider towing operations. These are a glider tow reference arc and a single descent speed marker. See figure 8 below.

Figure 8

Approach speed

Approach speeds for each type will vary. As a guide, in calm conditions, the approach speed should not be less than the minimum tow speed marker. Additions for wind strength and gradient should be applied to this.


1.10     RADIO PROCEDURES

A 720 channel radio, along with intercom and headsets is fitted to all tugs. The radio should be used for all towing operations. The headset doubles as an ear defender and provides for clear radio usage. The earphones are fitted with a separate volume control. PLEASE take care of the headset and stow carefully when not in use.

The radio will be used primarily for receiving Pilot’s name, Glider, any special instructions etc. and also the “Up slack” and “All out” signals. These radio messages have to be backed up by visual signals, which the wing tip holder will continue to do, however the forward signaller can be dispensed with under this system.

The frequency to be used will be 119.9.

The following stations should have radios;

               Station                                                                                                 Call-signs

               Tugs                                                                                             “XRAY INDIA

                                                                                                           ”CHARLIE ALPHA"

                                                                                                           “UNIFORM ALPHA”

                                                                                                                “YANKEE MIKE”

               Winch                                                                                                    “WINCH”

               Midfield bat                                                                                     “MIDFIELD”

               Launch point                                                                “DUNSTABLE RADIO”

               LGC Office                                                                                          “OFFICE”

These will be prefixed with “DUNSTABLE” if any conflict occurs. Likewise with several tugs operating, the launch signals should be prefixed by the tug in question, e.g. “XRAY INDIA UP SLACK”. The tug pilot should reply with his call-sign only, “XRAY INDIA” in this example, unless the request is not possible. The “ALL OUT” will be acknowledged by commencing take-off.

During midweek operations, only a few of these stations will be operating. However, a general transmission such as  “UNIFORM ALPHA LAUNCHING” should be made at the start of the take-off.

If you are doing something unusual, e.g. Landing in a different area of the airfield, taxiing across the winch cables or returning to refuel, then announce your intentions on the radio.


1.11     AERO-TOW SIGNALS

1.11.1     To order the glider to release

Rock the wings of the tug. The action should be positive, ideally 45° bank to the left then 45° to the right. The glider should release immediately, this will then  permit the right bank to become the parting manoeuvre.

This signal is often used during competition launches, where a “wave off” at 2000’ is the normal release method.

1.11.2     The signal from the glider pilot to say he is unable to release

The glider pilot should fly his glider out to the left of the tug as far as practical and rock the glider’s wings. In this case, operate the glider release and leave the tow rope with the glider. It may be necessary to tow to a suitable position before doing this.

NOTE; Some Gliding Clubs have a signal to inform the glider pilot that his air-brakes are open. We have no such signal and none should be attempted. See 1.12.2 Rejected Take-off and 1.12.3 Glider air-brakes open.

1.12     EMERGENCIES

1.12.1     General

Every pilot must be continually aware of possible emergency situations occurring during towing operations.

The Glider Release handle must be immediately accessible and used if the glider prevents your control of the tug.  Many accidents to tugs have occurred in the past due to the tug pilot’s failure to release his glider.  Whilst we must have concern for the glider pilot, the safety of yourself and the tug is paramount.

1.12.2     Rejected take-off

Once full power has been set, check the RPM, if it is not up to the normal value for the aircraft, reject the take-off. At around 20 to 30 knots check in the rear view mirror; if the gliders’ air-brakes are open, release the glider immediately and reject or take-off as appropriate.

If a take-off is rejected, then release the glider and roll on in a straight line as far as possible.  This will allow the glider space to manoeuvre behind the tug.

1.12.3     Glider air-brakes open

Attempting a take-off where the glider has its air-brakes deployed is extremely dangerous, in most cases the glider pilot will not realise the problem. An early release when airborne will probably result in a glider accident. In some cases the combination will not be able to climb and there is no alternative then, but to release the glider. If a climb is possible then the combination should be positioned onto base leg or finals such that when released the glider will make the landing area with its air-brakes fully deployed. Do not attempt to signal to the glider. Radio communication may be possible.

1.12.4     Engine failure

Tug engines are as likely to fail as other light aircraft engines, your knowledge and competency of emergency landings and the associated vital checks is essential.  On your first flight each day, check out the forced landing options.

Remember that a stopped propeller will steepen the “idle power” glide angle. Also the type of propeller fitted will affect the tug’s glide angle, a four-bladed propeller, in particular, will further steepen the glide angle dramatically.

1.12.5     Tug upset

From time to time over the years, tug upsets have occurred at low level from which the tug has been unable to recover, usually with fatal results. A glider pilots’ aero-tow training emphasises that correct position behind the tug is essential and that he must release if he is losing control. However, tug pilots must be vigilant during the early stages of the launch for any tendency of the tug to be pitched nosed down. Below 600 feet, monitor the tugs’ attitude and if a gentle back pressure is insufficient to prevent any nose down pitch - release immediately. Above 600 feet, the glider pilot may be given the opportunity of correcting the situation. Be aware that tug upsets can happen rapidly with little warning.

There are a number of factors which increase the possibility of a tug upset;

1.  A glider that is to be towed from a belly hook.

2.  Gliders with high set wings relative to the towing hook.

3.  Gliders with a low wing loading, usually older or vintage types.

4.  The presence of turbulent conditions, especially if associated with a strong wind gradient or if the wind is off the hill. The East run at Dunstable is particularly critical in this respect.

5.  Glider pilots with low hours and/or aero-tow experience.

6.  Lightweight pilots

7.  The use of short tow ropes will exacerbate the problem.

Figure 9

A typical sequence is shown in figure 9, with a simplified rope load/ angle plot in diagram 10. In reality the situation is worse than shown because the glider zoom climbs behind the tug, its total energy increases (simultaneous increase in height and speed). This energy can only come from the momentum of the tug and therefore its speed will rapidly decay. This means that just when a high down load is required to be generated by the tailplane/elevator to retain control and break the weak link on the rope, its capability to do so is vastly reduced by the decay in airspeed. This may result in the tailplane, and possibly the wing, stalling. Typically, up to 600 feet may be required to recover from an upset.

Also avoid a hasty transition from level acceleration to climb, as this will result in the glider becoming low relative to the tug. This can tempt the glider pilot to make a rapid recovery, with obvious potential for overcorrection.

Figure 10

In addition, there are other destabilising influences for both tug and glider pilot, such as re-trimming, flap and undercarriage retraction, instrument scan, etc. For the tug pilot, retracting flaps should be left to a safe height, at least 300 feet.

Since upsets are, fortunately, rare events and tug pilots may not have experienced any before, the overriding advice is; Any unusual behaviour of tug or glider in the early stages of the launch is cause for immediate release of the tow rope. The analysis can be done afterwards.


1.13     ACCIDENTS AND INCIDENTS

After an accident or incident involving a tug, the tug pilot concerned must ground himself and notify the CFI and CTP as soon as possible.  The accident or incident will be reviewed and tugging re-authorisation determined accordingly.

1.14     CHECKLISTS

There are no standard checklists issued.  Every pilot must therefore use checklists which enable him to operate the aircraft safely.  With reference to the section on Emergencies above, each pilot should have clear in his mind actions in the event of an emergency.  Guidance from the CTP or DCTP is available if required.

1.15     WHICH TUG TO USE?

The Aircraft Status board in the tug hangar will give the priority order for using the tugs and should be adhered to unless weather conditions preclude the use of a high priority tug. It will also show if a particular tug is unserviceable or out of check. This information is updated by the manager or the Aircraft Engineer. Further information on individual tugs will be found in their respective Tech. Logs.

1.16     REFUELLING

It is the tug pilot’s responsibility to refuel his aircraft if fuel tanks are indicating less than a quarter full and at the end of the day’s flying.

1.16.1 Exercise extreme care when taxiing towards fuel pumps, and make sure the overhead refuelling pipes are stowed and the general area is clear. The tug should be taxiied straight in and stopped with the propeller disc just short of  the white line.

1.16.2 Always connect the earthing strap to the exhaust pipe before attempting to refuel.  Ensure all aircraft electrics are off.

1.16.3 Fill all tanks of the tug to FULL.  The only exceptions to this may be prior to launching a competition grid, before setting out on an aero-tow retrieve or before maintenance. NB; The auxiliary tank on G-BVYM is normally left empty.

1.16.4  After refuelling, stow the overhead refuelling pipe, stow the earthing wire and move the tug away from the pumps for starting or parking

1.16.5 Record the uplift and meter readings in the Fuel Record book.

1.17     TUG RECORDS

1.17.1     Technical Log

The Tech. log is an important document as it provides a pilot with a current status report on the tug.  It also records tug hours and forms a record of defects.  The information from the Tech. log is used by the Aircraft Engineer to schedule maintenance checks and keep the required tug records.

The first page of the Tech. log itemises all outstanding defects and states when rectification will take place.  Any flying restrictions will be written on this page. It is for the pilots information, either when taking over a tug or before completing the D.I.  All items on this page will be entered by the Aircraft Engineer or CTP only.

A Tech. log page should be completed for each day’s flying.  This page is completed in basically two stages.  After the D.I., the pilot will enter any new defects, the tacho time, date and sign for the D.I.  At the end of the day the last pilot will add any further defects, enter the tacho time, complete the hours column, add the number of tows done and sign the Tech. log.  If during the day defects occur then they should be entered into the Tech. log at the time.

The Aircraft Engineer will vet all entries regularly.  The Aircraft Engineer will arrange rectification or defer rectification to a specific check and annotate the Tech. log accordingly.  The daily pages, once vetted will be removed.

Any queries regarding Tech. log entries should be made to the Aircraft Engineer or CTP.

1.17.2     Tug Log Cards

Records all information necessary for the treasurer to correctly charge Club members for aero-tows.

At the end of the day these cards should be deposited in the Club office or with the resident tug pilot.

1.17.3     Fuel Record

This is kept in the shed and should be completed for all uplifts of fuel.

1.17.4     Pilot’s Records

Details of pilot’s licence numbers, renewal dates, medicals, hours etc. will be held by the CTP and shown in Appendix 1, a current version of Appendix 1 will be on display in the Club office.  For PPL holders, new renewal dates should be advised to the CTP. Please annotate the office copy with any other changes.

Please note that renewals are strictly the responsibility of the individual pilot.

1.18     TUG EQUIPMENT

The standard issue of removable equipment to each tug is;

2 tow ropes; 1 rope in use + 1 spare on board.

1 Peltor headset.

1 Clipboard, for tug log cards and pen.

1 Hand fire extinguisher.

The Tech Log and a copy of the Tug Pilot Manual.

Each tow rope is fitted with two weak links. A serviceable weak link will contain two staples, coloured either red or yellow. If a staple is broken or missing, it must be replaced before use. The yellow staples are rated at 1100lbs breaking strain, they are identified on the tow rope by a dayglo flag and one square wear protector, this end always attaches to the tug. The red staples are rated at 900lbs breaking strain and are protected by three square wear protectors, this is always the glider end.

Spare ropes, short field retrieve ropes and dual aero-tow ropes are stored in the tug hangar. Specialist ropes may not necessarily conform to the above weak link system.

Try and keep tow ropes clear of the “metalled” perimeter track. Cars and tractors running over the rope cause premature wear.

Do not leave tow ropes lying on the field overnight.  One rope may be “snaked” on the hangar floor if its’ use next morning is anticipated.

Aircraft cleaning equipment is available in the tug hangar.

1.19     TUG HIRE

Tug aircraft may on occasions be available to hire. However, approval will always be required from the CFI or CTP. The pilot will be charged according to the charges shown in the LGC price list.


1.20     BOOKING IN/OUT

It is a legal requirement that all powered aircraft movements not starting and finishing their flights at Dunstable (i.e. most flights other than normal aero-tows) should be recorded. A movement book is located outside the main office, it has two sections, the first for visitors taking details of departure point and destination and a second section for LGC tugs recording either a destination or a departure point.

All aero-tow retrieves, positioning flights or hire flights should be entered along with the pilot’s signature.

1.21     GRID DAYS  

The grid system may operate on a week-end or Bank Holiday cross country day when weather conditions are expected to suit cross country flying.

Please note the following requirements placed on ALL tug pilots when a “Grid” day is declared;

A “Grid” day will declared by 8:30 on a week-end day. If it is, then all tugs will be made available for the later grid launch.

If, when you arrive a serviceable tug is still hangared, then you should pull it out, DI it, taxi it to the relevant launch point and carry out the power check. This should be done regardless of who subsequently flies it.

Having done this task, if necessary, you may then turn your full attention to your gliding.

At Grid launch time, if there are not enough non-cross country tug pilots to fly the tugs, it may be necessary to help launch the first part of the grid. Towards the end of the grid it will be expected that you park the tug and you can then expect a priority launch at the end of the grid.

Tug pilots not flying cross country will be expected to return any “discarded” tugs to the hangar.


1.22     AERO-TOW RETRIEVES

A number of aero-tow retrieves are carried out each year. Generally, requests for “Airfield” retrieves will be accommodated if at all possible. “Field” or non-airfield retrieves will generally be discouraged because of the high level of associated risk. However it is accepted that some “Field” retrieves will be necessary, for example, to retrieve a K21 and bring it expeditiously back on line at LGC.

1.22.1 AIRFIELD and FIELD Categories

Retrieves will be one of two types, namely AIRFIELD or FIELD. Appendix 2 of this manual lists all airfields that may be considered for AIRFIELD retrieves. If the airfield is not listed or is a farmer’s field, playing field or private strip, then it is to be considered a FIELD.

1.22.2 Pilot Requirements

To carry out an AIRFIELD retrieve, a pilot must be AIRFIELD or FIELD rated (See Appendix 1).

To carry out a FIELD retrieve, a pilot must be FIELD rated.

AIRFIELD rating;       To obtain an AIRFIELD rating a pilot must acquire a certain amount of aero-towing experience after completing basic training. This will normally be 150 tows or 25 hours. Additionally a briefing will be given by the CTP before being listed.

FIELD rating;             FIELD ratings are deliberately limited to a few pilots. It requires a high degree of competency on Super Cub aircraft, a short course on theory, and some flying practice usually with the CTP. Once qualified it is important that a number of field retrieves are carried out in order to maintain competency. This is the main reason for limiting numbers.

1.22.3 Procedures

Before embarking on a retrieve it is important that the following points are addressed;

1.         Permission must be obtained from the farmer or land owner to carry out an aero-tow retrieve from their land.

2.         Permission must be obtained from the CFI, CTP or their deputies.

3.         Tugs should normally be refuelled before departure.

4.         The Tug Pilot must Book out. The Booking In/Out book is located just outside the main office.

5.         A spare rope must be carried.

6.         A suitable map must be carried.

7.         Consider which aircraft to use. The DR300 is probably most suitable because of it’s high cruise speed and navigation equipment. Although for short distances any tug may be used.

8.         Check Appendix 2 for any special procedures. The latest and most up to date Appendix 2 is located on the Office Notice board.

9.         If radio procedures are required, and most airfields do, then the Pilot must also hold an R/T rating.

10.       Be aware of the logging procedure (see 1.22.4 below) and note Tacho time before departure.

1.22.3 Techniques

Before take-off ensure that you do the following;

Work out your contingency plan to cover actions in the event of an aborted take-off or in the event of rope break (release) soon after take-off. Brief the Glider Pilot accordingly.

Decide on a tow speed to suit glider and pilot. Decide how the signalling is to be arranged and any other relevant details.

Try and ensure you have radio communication between Tug and Glider.

After take-off, do a normal climb out until reaching 500’ agl, then accelerate to your agreed tow speed. Once a safe height has been reached or a chosen altitude, reduce power to achieve a slight climb or level flight.

Try to avoid the need to descend on tow, as it can be quite destabilising. If a descent is needed for cloud or airspace, then reduce power slightly to achieve a smooth 100-200 fpm descent, anything more will require the glider to use his airbrakes.

Surging is when the tow rope slackens and tautens continually. It can be caused by turbulence, lack of concentration on the part the Glider Pilot or by descending too quickly or inadvertantly. Surging can occur during level flight, but is most likely to occur during descending flight. The best solution is to apply power and accelerate or climb slightly until the surging ceases, then slowly return to the desired stable state.

Remember that until the glider releases, you are in charge of both aircraft and responsible for navigation and any RT calls.

1.22.4 Logging Procedure

The reverse of the Tug Log card contains a self explanatory form for recording aero-tow retrieves and other non-towing flights.

Note that for short retrieves, certain minimum charges will apply. A charge equivalent to a 3000’ aero-tow will be applied for a retrieve from Halton and a 2000’ charge for a retrieve from Eaton Bray or similarly close field retrieve. The times should still be recorded as above and the Office staff will apply these minimum charges.

Occasionally a visiting pilot will want an aero-tow retrieve from Dunstable. All the points in 1.22.2 must covered, in addition the Tug Pilot must take responsibility for ensuring a correct charge is made. The Manager should be approached in the first instance, in his absence, note as much relevant information on the Tug Log card so that a subsequent charge can be made.

1.22.5 Eaton Bray

Eaton Bray is a local small strip often used by LGC gliders. Pilots must be specifically cleared to tow from there.

In recent years the strip has become very restrictive, with the width being reduced to little more than 20 metres and with numerous obstacles at the South East end.  Currently take-offs should only be made to the North West and with experienced Glider Pilots. Tug Pilot’s who have not aero-towed from there recently should seek advice on the current situation before attempting a retrieve.

1.22.6 Feedback

Please feedback any useful information gathered whilst carrying out a retrieve in order that Appendix 2 can be kept up to date and valid.

 

 

 

2.     ROBIN DR400 and DR300 OPERATING NOTES

2.1     INTRODUCTION

The following notes and procedures have been developed from the DR300 and DR400 Flight Manuals, knowledge of the engine’s cooling characteristics and many years of Aero-towing experience. Please adhere to the procedures listed. The Flight Manual may be consulted for supplementary information, a copy of which is kept on the aircraft. There are some differences between the types of Robin, notes specific to the DR300 are italicised, notes specific to G-LGCA are in bold.

2.2     GENERAL

2.2.1   In order to avoid damaging the flaps, the flaps should always be down when parked or hangared to facilitate entering or leaving the aircraft. Also when anyone approaches the aircraft lower the flaps to permit access.

2.2.2   The electric fuel pump should be ON whenever the engine is running.

2.2.3   On the ground the best engine RPM for cooling and avoiding plug fouling is 1000-1200 rpm.

2.2.4   All Robin aircraft are currently fitted with a wooden propeller, therefore there is no RPM restricted band.

2.2.5   Ensure all articles in the aircraft are strapped or tied down. The wide expanse of perspex is particularly vulnerable to loose objects.

2.2.6   A cylinder head temperature gauge is fitted. It can be switched between cylinders. For normal use it should be selected to cylinder No. 4.

2.2.7   An electric turn indicator is fitted. It is installed for emergency use only and is normally off. If required, it can be started by resetting the circuit breaker. It will provide useful information within 20 seconds. CA has a turn rate indicator and it should NOT be switched off.

The DR300 also has an air driven artificial horizon which cannot be turned off.

2.2.8   The DR400 has only two seats fitted and is only insured for one pilot and one passenger.

2.2.9   DR300 Fuel Tank usage; For most operations the auxiliary fuel tank will remain empty. If it is filled then the aircraft should be operated down to about half main tank. The auxiliary fuel knob should be pulled out, which will effectively refuel the main tank from the auxiliary tank. Once the auxiliary tank is empty the knob should be returned to the OFF or in position. Note; the system is NOT designed for the engine to run from the auxiliary tank.

2.2.10 CA has an hours meter which should be used for recording hours instead of the tachometer.

2.2.11 DR300 Canopy;  Two gull wing doors with an awkward latching lever. Care is needed to ensure the locking pins are located correctly. There is a bottom pin beside the door latch and another at the top in front of the locking lever.

2.2.12 A Garmin 100 is fitted to supplement the VOR for cross country flying. It is important to remember to switch off the unit separately, by pressing and holding the OFF switch until the display blanks, before engine shutdown. Failure to do this will cause the internal nicad battery to flatten.

2.3     DAILY INSPECTION

Pilots must complete a daily inspection in accordance with the LAMS (Light Aircraft Maintenance Schedule - See Appendix 5) requirements and this must be recorded in the Tech. Log before flying commences.

In addition, special attention should be given to the following items;

1.  Nose wheel leg - inspect for cracking particularly at the attachment brackets. This is important in view of the rough nature of the airfield.

2.  Condition of the main landing gear - remaining oleo travel must be 2.75 inches or more. The top of the wheel fairing must be below the check hole in the fixed fairing when the aircraft is empty.

3.  Cylinder heads - Look specifically for any cracks on each cylinder head. The most likely area is between the exhaust port and the spark plug hole on the lower side of the cylinder, but