Briefing: Out-Landings (WIP)

Introduction

Aim: You will know when and how to select a field for a safe out landing, and how to execute a safe landing into it.

What do we know?

Who has landed away from their normal airfield?

What was different about it?

When does the Out-Landing process start?
  • Most training occurs within Gliding Range of your home airfield
  • Planning an Out-Landing occurs before you leave Gliding Range
Gliding Range

Discussion…

  • What is your glider’s real-world performance?
  • What might affect it?

Make a sensible assumption of your achievable glide angle.

What about ‘Arrival Height’?

  • How much is required?
    • What might affect it?
    • How much do you want?
  • What is your flight computer assuming?

How far will you assume you can go with the height you have?

  • Stay within that range of your airfield until you are at a height that puts you within range of landable options ahead.
Decision Heights

The height at which you make your decisions may depend on the terrain ahead of you.

Inhospitable Areas
  • Know your landing options.
  • When your height decreases towards the minimum needed for a safe glide to reach a known option (including a circuit), fly towards it and land if you do not find lift.
Example – your landable field is 10km ahead
  • Assuming 1:20 glide angle (e.g. in a glider with 1:40 Best LD)
  • You’d need to be approximately 2,500′ above the field to be just within a safe gliding range:
    • 10km / 20 = 0.5km, approx 1650′
    • Plus 800′ for a good look around it including a circuit
    • = 2450′
    • Even this assumes there are no surprises on the way, or on arrival.
Hospitable Areas
  • Tactics vary with height
    • Above 2500′ AGL, have landable areas ahead
    • Between c. 1500′ and 2500′ AGL, have identified landable fields within a safe gliding range
    • Below c 1500′ AGL choose a field, and soar locally to it
      • Search for lift
      • Land if none found
      • Keep it within range if you find lift and move on, until another option is available
      • At c. 1000′ AGL make the decision to land

Before you fly, set your decision height, below which you commit to land (or attempt and engine start).

Field Selection

Wind and Six S’s:

Wind

The Wind Direction and Speed may be found from area forecasts. Mark it on your chart.

Wind Direction
  • Can vary based upon topography
  • Typically backed by 30 degrees compared to soaring height
  • Nav computer, thermal drift and cloud shadows indicate wind direction at height
  • Surface movements (crops, water, smoke) indicate direction at ground level
  • Note the direction relative to a visible feature, or the sun

Landing into wind has a significant effect on the size of the field that is required.

Wind Speed
  • Can vary based upon topography
  • Nav computer, cloud shadows indicate wind strength at height
  • Surface wind speed is typically half of that at soaring height
  • Surface movements (crops, water, smoke) indicate the wind strength at ground level

A light wind requires a large field, and can make the determination of the wind direction difficult.

Size
  • Field sizes will vary between regions, e.g. in different sections of a XC task.
  • Hillier areas tend to have smaller fields than flatter areas.
  • Bigger is better, but…
    • Beware of large fields being divided into small ones by (invisible) wire fences – look for signs mid-field, such as troughs and surface colour changes, which may indicate a division
  • Consider landing diagonally across a small field, to maximise the available space
  • The largest crop-free field in the area may not be large enough – it would be better to select a larger field in crop.
  • Effective Size is affected by Surroundings (see below)
Slope
  • Slope is difficult to see above c. 1500′, and can only be assessed well below c 1000′ AGL. If the slope is visible higher than this, it is probably too steep.
  • Slope should be assessed from the side.
  • A flat field is best.
  • Landing up a significant slope requires care:
    • extra speed is required
    • the approach speed must be monitored closely to avoid a shallow approach, due to the perspective of the upslope on approach
    • apply wheel brake to avoid rolling backwards
  • Landing downslope is to be avoided
  • Fields parallel to rivers and railways lines are likely to be flatter
  • Ground tend to rise away from rivers.

Surface
  • Crops
    • Vary in height (and density)
    • Vary through the year
    • If you can see soil through the crop, then the crop is probably short enough to land in
    • Maintain your awareness of crops by looking at fields as you drive through the countryside
  • No Crop
    • Tilled is better than ploughed
  • Tramlines (tractor wheel tracks)
    • Landing across them could be damaging
  • Look for other surface features, e.g. drains, fences and wires (and poles)
  • The smoothness of a surface cannot be detected until the ground run: make it short… hold off, full airbrake on touchdown, wheel brake.

Website: Field Crops – for Glider Pilots

Shape
  • Square fields provide more options than narrow ones.
  • Consider landing diagonally – but beware of furrows and tramlines.

Surroundings (or Sticks)
  • Obstacles may be buildings, trees, roads, etc, or less easily seen wires between trees or poles.
  • Obstacles on the approach significantly affect the landing distance available:
    • If your approach path is 1:8 for example, you’ll need eight times the height (plus a safety margin) of any obstacle before rounding out.
  • Place your Reference Point well into the field, so that you overfly the boundary at a safe height.
  • Once clear of obstacles, you may consider opening the airbrakes more fully.

Stock
  • All animals are best avoided.
    • Sheep jump
    • Cows are inquisitive
    • A single cow is probably a bull
    • Horses are expensive
    • And they all move

Whilst the selected landing area would ideally meet all these criteria, a compromise may be necessary.

Judging Height
  • At height, it is difficult to estimate your height above the ground
    • Use every method available to monitor it
  • Altimeters tell you the height above a datum – which are you using, QFE, QNH or QNE?
QFE, QNH, QNE
  • QFE: Reads zero at the location where it was set (typically the departure airfield). Displays height relative to that location.
    • The barometric pressure subscale will show the local atmospheric pressure at the time the subscale was set.
  • QNH: Shows altitude above mean sea level.
    • The barometric pressure subscale will show the local atmospheric pressure adjusted to sea level, at the time the subscale was set.
  • QNE: Used to determine ‘Flight Level’
    • e.g. A reading of 6500′ would equate to FL65
    • The barometric pressure subscale is set to 1013.25 hPa (29.92 inHg).
  • QNH is recommended for XC flights.
    • It also for communication with ATC, until you are high enough to use Flight Levels
    • Charts show spot heights
    • Subtract the spot height from the QNH altimeter reading to estimate your height above the ground.
  • Navigation computers can show height AGL, if selected!
  • Visual checks may confirm the information from your instruments
    • Look for the size of ground features
    • “When cows have legs, it is time to look for fields. When sheep have legs, it is time to land”
Make the Decision to Land

In flight, when you make the decision to land: make it a commitment – e.g. select a field if not already done, or put your wheel down and commence your pre-circuit checks.

Why should you commit?
  • Thermalling low down has its own dangers, and can drift you away from the chosen field
  • Failing to find lift places you too low for a safe circuit and approach
Turbo (etc) Considerations

The trouble with turbos…

  • Increased pilot workload, when already low
  • Risks increase, and errors occur
    • Engine Start techniques vary, some requiring significant loss of height.
    • Engines cannot be relied upon, even when they start.
    • A failed engine start, especially with the pylon erect, will consume a lot of height, and degrade your glide angle.

Make your decision height high enough to allow for a potential failure, and be ready to land in the selected field.

Circuits for Out-Landings
The Circuit
  • Should be similar to those at your home airfield.
  • In a crosswind, place the High Key to the downwind side.
  • The field is likely to be smaller than your home airfield. Avoid cramping the circuit:
    • High Key is likely to be well upwind and to one side of the field.
    • Base leg may be a couple of fields downwind.
    • Monitor your Height, Angle and Distance to the reference area.
  • Inspect the field closely during the downwind leg, checking for slope and obstacles on the ground run and approach, such as wires.
  • Normal rules apply: monitor airspeed and attitude, especially during turns.
  • If space allows, place the landing area well into the field, to ensure you overfly obstacles on the boundary.
Approach and Landing
  • Look out for unseen wires across the approach.
  • A well braked approach will lead to a shorter landing than a shallow one.
  • Once on the ground, stop as quickly as possible, to avoid small but damaging obstacles.
Running out of Space
  • Ground loop if necessary, while you still have the energy to do so.
  • It is better to hit the far hedge than the near one.

After Landing
  • If on an airfield, move the glider out of the way, off the runway.
  • Secure your valuables.
  • Note your location, and that of an access gate.
  • Contact your home club and retrieve crew.
  • If in a field in the UK, inform D&D by phone (01489 612691), to avoid an unnecessary emergency response.
  • Place a note in the the canopy explaining you are safe, with a contact number.
  • Find the land-owner, inform them of your arrival, with apologies.
Recap

When should you start to select a field for an outlanding?

When is it safe to fly beyond gliding range of your home airfield?

How do you know how high you are above the ground?

What are the features of a good outlanding field?

What actions do you take after landing?

TEM

Threats
It is a stressful situation

Mitigation:

  • Practise and refresh your skills in a motor glider.
  • Make the decision to land at a safe height and commit to it.
Few good fields available

Mitigation:

  • Plan your task to increase your chances of finding good options.
  • Base your routing decisions on landing options, in good time.
Unseen obstacle or poor surface

Mitigation:

  • Make the best inspection you can.
  • Pick a big field and land well in.
Errors
Trying too hard to stay airborne, delaying your choice of field.

Mitigation:

  • Prepare for, and arrange your retrieve before you launch.
  • Make your decision early, to match your (in)experience.
  • Do not lose sight of your chosen field.
Excessive focus on the chosen field, leading to loss of speed control.

Mitigation:

  • Fly a proper circuit and look over the nose during turns.
  • Note the position of the field relative to other features, so that you can re-find it easily.
BGA Resources

The BGA webpage on Field Landing provides many useful resources.