Including the Scan Cycle and Drift
Introduction
Aim: You will understand how to look out for other aircraft, whilst maintaining your attitude, monitoring your instruments & keeping the glider going where you want.
What do we know?
- What are your experiences of flying straight?
- How well were you able to spot other gliders, maintain the speed and keep going where you wanted?
- What made it difficult?
Lookout & The Scan Cycle
What is it?
A workload management system…
“The method used to balance looking out with monitoring the glider’s attitude and checking the instruments.”
90% ‘Head Out of the Cockpit’
Lookout
Why do we need to do it?
- We don’t fly in lanes
- Objects don’t get big until they’re too close
- Our eyes are not adapted to these dangers:
- Small arc of detailed vision
- Our brains fill in the gaps
- Most of our retina detects movement, not detail
- The thing that will hit us is not moving across our field of view, and it grows slowly.
Attention test video
Who does it? Everyone
When? 90% of the time, at least!
How do we fit it in with checking the instruments? The Scan Cycle.
The Scan Cycle Method
LAI: Lookout – Attitude – Instruments
- Lookout:
- Look ahead, focus on, above & below the horizon
- Repeat at 45 degrees, 90 degrees, & all the way back to one side
- Return to Ahead via Above, like upside-down pair of spectacles
- Look over the nose, check and correct Attitude
- Wings level, String central, Picture stable
- Check the Trim
- Glance at Instruments:
- Vario: is the glider in rising or sinking air
- Altimeter: do you have enough height to stay on the same course, or should you return to the airfield?
- Repeat to the other side, completing the upside-down spectacles
Diagram of the Scan Cycle
The method is flexible: Focus on areas of greatest risk for the current phase of flight:
- Anywhere
- Circuit
- Thermal
- Ridge
Rules of the Air
It is everyone’s responsibility to avoid a collision.
| Situation | Rule |
|---|---|
| Give Way: | Balloons have right of way. The primary rule is to avoid collisions with anything. |
| Converging: | On the right is in the right. |
| Head On: | Turn right. Ridge rules vary from this. The glider with the ridge on its right is in the right. The glider with the ridge on its left should turn out from the ridge to give way. |
| Overtaking: | Pass on either side (UK only). On ridges, pass on the ridge side (to allow the other glider to turn away from the ridge). |
| Landing: | The lower glider has priority (but may not cut in front of a glider on Final Approach). An aircraft making an emergency landing has priority. |
FLARM and other Conspicuity devices
- Benefits as an aid to Lookout
- Limitations as an aid to Lookout
Flying Straight
Why fly straight?
- Getting from A to B efficiently (minimum height loss)
- Approach to the landing area
- Landing on a runway
- Spot landing
- Prerequisite skill for Winch Launch or Aerotow
- To feel for thermals
How do we know we are flying straight?
- Wings level
- String central
- Target is fixed in the canopy – Picture not changing
How do we return to straight flight?
- Aim for a ground feature, or cloud: your Target
- Correct the Attitude with gentle, coordinated aileron and rudder if
- Wings are not level
- String is not central
- Adjust pitch attitude with elevator
- …which is fine so long as there’s no drift.
Video
Of a demo flying straight in still air:
- It starts by showing the glider is stable with no control inputs.
- Mute the video if you do not want the commentary.
Flying Straight in a Crosswind
A Headwind or Tailwind may be fully in line with your direction of travel, and whilst affecting your groundspeed, it would not affect your Track over the ground.
A Crosswind is one which is not in line with your direction of travel. It pushes the glider away from its Target, causing Drift. To track directly towards your target, you must Crab by flying on a Heading slightly upwind of your target.
To Crab in a straight line:
- Fly on a Heading upwind of your Target, by estimating the drift.
- Keep the Target fixed in the canopy (off centre, on the downwind side).
- Adjust the crab angle to prevent the Target moving side to side.
Illustration
1 to 2: There is no crosswind. No correction for drift required.
3 to 4: Crosswind from the right. Heading correction results in a straight track to the target.
5 to 6: Crosswind from the right. Glider keeps heading at the target, resulting in a longer curved track.
The Scan Cycle remains the same
- Lookout
- Attitude (including Track) – correct as needed, using gentle coordinated controls:
- String straight
- Wings level
- Picture not changing
- Instruments
Video
Demonstration of the difference between heading and track in a crosswind. Mute it to miss the commentary. The use of the runway is purely illustrative.
Recap
- How do we perform a scan cycle?
- How do we stay on track whilst looking out?
- What is a crab and why would we use one?
- Who has right of way when gliders are converging?
TEM
There shouldn’t be any – the scan cycle embodies safe flying. But don’t forget to also include height management and staying in range of the airfield in your checks!
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