Black Mountains Gliding Club
Some notes for visiting pilots.
Daily briefingA short daily briefing will be given at 10am in the briefing room behind the clubhouse. All pilots should attend. In the event of poor weather the duty instructor may announce re-briefing at another time. Any visitor who has missed the daily briefing must have an individual briefing from the duty instructor before flying.
Flying in the circuitCircuit planning at Talgarth requires more thought than most other sites because it is a smaller site. You will not find the practical application of your skills any more difficult than your home site, but you have less room for error or complacency.
General LayoutThe field slopes away from its Southern edge in all directions, like an upturned saucer.
The Southern edge has a tall hedgerow, trailer park and hanger. For this reason, it is generally better to fly your circuit on the North side of the field.
Turning in early options are much improved if you are on the North side of the field. From the north most approaches are upslope with few obstructions. From the South most approaches are downhill with significant obstructions. (Figure 1)
If you have to choose between landing downhill and into wind or uphill and downwind, choose to land up the slope.
On the ground
Please be well prepared, get your checks done in good time. You will not be thanked for unnecessary delays.
Radio checks are on 130.1. The tug pilot will happily oblige. Your call should be - Papa alpha, followed by your call sign, radio check please.
Often you will find you are taking off down slope. This is good news for take off performance, but can also catch the unwary.
There are several good fields in the valley, but do not rely on any particular field being available to you---farmers do move sheep around!
Your pre-take off check should include:
The tow-plane will fly towards the mountain. The mountains obscure the natural horizon. Maintain your position with reference to the distance the tow plane appears up the canopy. When approaching high ground you may be tempted to get high, please resist it.
When approaching the mountain, resist any temptation to move away from the hill---this will swing the nose of the tug towards the hill!! Your task is to remain in station behind the tug.
On release, be absolutely certain the rope has gone. Wait and see it go. The tug may be within close proximity of the hill, and would prefer not to be tipped towards it. Once sure, make a climbing turn towards the hill, the tug will descend away from the hill.
Return to the field
When approaching from the South, the field can be difficult to spot; the trailers are screened by the hedgerow. If in doubt locate Y Das and Talgarth hospital, the airfield is between the two and will become more obvious as you get closer.
Always check the windsock before deciding your landing direction. Wind conditions change more frequently in hilly areas.
Listen out on the radio; other gliders will often make a radio call when downwind in the circuit; this will help your situational awareness. If it is busy, you may decide to continue soaring until the rush is over.
Considering the wind
Hill sites can suffer from 3 different wind characteristics.
Wind gradient is caused by friction with the ground, resulting in higher winds aloft and a progressively weakening wind as we descend. A dynamic loss of airspeed is to be expected in a wind gradient, and extra speed is required to provide a safety margin.
Clutching hand is caused by the airflow following the contours of the ground. The closer to the ground, the more pronounced the downward vector becomes. Even relatively light winds can produce significant sink as you approach the lee of a slope. Any uphill landing at Talgarth has a potential for clutching hand, (Figure 2)
Turbulence is caused by the airflow being disrupted in some way, trees and buildings are the most common causes. Wave rotor is the primary cause at Talgarth. Easterly wave can cause severe turbulence, and take-offs with a southerly wind can be affected by turbulence off the trees.
Intercepting and maintaining a 2/3 airbrake approach ensures the risk of a late undershoot minimised, because airbrake can be reduced if necessary at the latter stages of the approach. (Figure3) It also keeps you out of the worst of the clutching hand. If you get caught in clutching hand it is absolutely relentless and goes all the way to the ground---if you do get caught, increase speed, get into ground effect, do not attempt to stretch the glide.
Down wind Leg
The landing direction is rarely the same as the take off direction; the anticipated landing direction is provided at the morning briefing. It is still your responsibility as the pilot to check the windsock and review the landing direction.
It sounds obvious, but the downwind leg is parallel to the approach direction. Many pilots get too cramped because there is no obvious line to follow. Try to visualise an extended runway (a line running across the country side and use that line as your guide. Figure 4 shows the general idea for the Southwest approach (Runway 23).
When judging your circuit you cannot use some of the cues you have become accustomed to. The terrain around you varies in height, you are in effect landing on a platform. Some features (Y Das) are higher than you. Remember your basic training and judge the angle between you and your reference area, other factors may be deceptive.
In the interests of safety, it is preferred if you make a radio call early on the downwind leg. This is not mandatory, if you are too busy, concentrate on the flying and leave the radio.
Using 130.1 MHz , example - Talgarth---your callsign---downwind---right for 23.
If another glider is in circuit indicate your position in landing order. - Talgarth---your callsign---downwind right for 23 ---number two.
DO NOT WORRY ABOUT THE EXACT WORDING.
Most approaches are upslope, add 5 knots extra to allow for the roundout.
The markers are very important; do not plan to land before them. On 23, they indicate a significant change in slope, on 09 they mark the line of the electric fence.
Again the approach up a slope can be deceptive, you may feel too high (and of course you may be), your basic training will help you again---if the reference area is going up, you are undershooting.(Figure 5). If the runways are obvious (after grass cutting) the effect is more obvious.
You will notice that the complex slope makes the markers look a disproportionate distance into the field, you should only be interested in the apparent vertical movement of the markers, not the distances. Sub consciously there is a risk you will want to land short---after all who would want to waste all that landable area in an already small field!!
The ground run
I hope you enjoy your flying at Talgarth. Keep it safe, and we will enjoy your visit too.