Precautionary Search and Landing — Theory

Precautionary Search and Landing

CASA Recreational Pilot License (Aeroplane) — CASA Sample Syllabus Lesson 24, Pre-flight theory

All text and presenter notes in this briefing are licensed under Creative Commons BY-SA 4.0. More info

Precautionary Search and Landing — Theory

You're the pilot

  • You're flying a cross-country in a school aeroplane, on your own.
  • The forecast said cloud "improving later". We'll fly it one step at a time, and at each step you decide: continue, divert, or land.
Precautionary Search and Landing — Theory

Step 1

  • Cruising at 2,500 ft above the ground, 30 minutes from home
  • Cloud base is lowering — about 3,500 ft now, and it has been dropping for ten minutes
  • Visibility is still good, farmland everywhere, plenty of fuel

Continue, divert, or land?

Precautionary Search and Landing — Theory

Step 2

  • Cloud base is now about 2,800 ft, so you descend to 2,000 ft to stay clear
  • Visibility is down to 8 km, with rain showers ahead
  • 22 minutes from home, still plenty of paddocks around you

Continue, divert, or land?

Precautionary Search and Landing — Theory

Step 3

  • Cloud base is about 1,800 ft and you're at 1,200 ft
  • Visibility is 5 km, and the ground is rising ahead
  • Last light is in about 40 minutes, and the paddocks are getting smaller and fewer

Continue, divert, or land?

Precautionary Search and Landing — Theory

Step 4

  • Cloud base is about 1,000 ft and you're at 700 ft
  • Visibility is 3 km, with rain across your track
  • Trees and a ridge ahead, the last good paddock is behind you, and home is 15 minutes away — if you can see it

Continue, divert, or land?

Precautionary Search and Landing — Theory

Which step was your last good option?

  • Most of us would say step 3 or 4 — the point where it's obviously bad
  • But at step 1 or 2 you had height, visibility, daylight, fuel, fields behind you, and a calm head
  • Nothing about the engine changed. Only your options did
Precautionary Search and Landing — Theory

Options drain faster than you think

An illustrative chart with time along the horizontal axis and options along the vertical axis. A curve starts high and falls steeply, then flattens near zero. A green zone early on is marked Decide here, covering steps 1 and 2. A red zone at the end is marked Committed, covering step 4.

Precautionary Search and Landing — Theory

Today's flying

Unlike Lesson 17, the engine is still running today — this is about judgement, not an unmistakable failure. The same discipline applies: decide early, while you're still in full control.

A precautionary search and landing is for anything you're not happy with, not only cloud and last light:

  • Weather closing in, fuel getting tight, or daylight running out
  • Oil pressure fluctuating, or another engine indication that isn't right
  • A sick or distressed passenger
  • Becoming unsure of your position

The aim today: build the judgement to decide early, and the plan to act on that decision calmly.

Precautionary Search and Landing — Theory

Theory Lesson Overview

Precautionary Search and Landing — Theory

Learning objectives for this lesson

By the end of this session, our aim is to be able to:

  • Describe the circumstances that call for a precautionary landing, and why the decision must be made early
  • Configure the aeroplane for a precautionary/poor-visibility cruise
  • Apply the field-selection criteria to choose and inspect a suitable landing area
  • Describe the vital-actions sequence, including the PAN call and passenger brief
  • Revise the short-field landing technique from Lesson 22

And then later in our actual flight: we'll fly the search, inspection and approach sequence for real, from varying positions and simulated conditions.

Precautionary Search and Landing — Theory

Waypoint 1 — Vital Actions

Precautionary Search and Landing — Theory

First — your workbook, and Lesson 17

Quick recall before we go on:

  • Name a few circumstances that might force a precautionary landing
  • Turning from downwind to into-wind, low over the ground — how does the aeroplane appear to behave?
  • What's the difference between a PAN call and a MAYDAY call?
  • From Lesson 17: what are the field-selection criteria, and what's the standing priority order?
Precautionary Search and Landing — Theory

The vital-actions sequence

Once you've decided, the sequence runs in order:

  1. Decide — early, while still in full control, shift to being a "landing pilot"
  2. Configure — for a precautionary/poor-visibility cruise
  3. Select — search the area and choose a field against your WOSSSSET criteria
  4. Communicate — the PAN call
  5. Prepare — brief the passengers
  6. Inspect — fly the inspection pattern to confirm the field, keeping it in sight
  7. Land — the short-field technique, then secure the aircraft
  • Imagine you're on a genuine cross-country along today's planned route, not just training close to the aerodrome. What's your trigger — the one sign that would make you decide now, not "wait and see"?
Precautionary Search and Landing — Theory

Configuring for the search

Once you've decided, set the aeroplane up to search safely:

  • Slow, safe cruise — enough margin above the stall to manoeuvre and look, not so slow you're working hard just to stay in the air
  • Some flap — improves the view over the nose and lowers your safe manoeuvring speed
  • Height — low enough to assess the ground, high enough to keep options and height in hand

Fly the aeroplane first. Configuring, searching and selecting all happen with a hand still on the controls, not instead of flying.

Precautionary Search and Landing — Theory

Waypoint 2 — Search and Select

Precautionary Search and Landing — Theory

Low-flying hazards

Flying low and slow to search and inspect brings its own risks — recap your Lesson 17 WOSSSSET field-selection criteria, then add the hazards it doesn't cover:

  • Wires, poles and towers — often invisible until close; scan the horizon, not just the ground
  • Terrain and turbulence — expect sink and turbulence in the lee of hills, trees, and buildings
  • Livestock and people — avoid frightening animals or overflying people at low height
  • Changing groundspeed in the turn from your workbook — a genuine effect of wind drift, not a fault with the aeroplane; fly the attitude, not the picture

Low flying earns its own dedicated lookout — the margin for a surprise is smaller down here.

Precautionary Search and Landing — Theory

Waypoint 3 — Communicate and Prepare

Precautionary Search and Landing — Theory

Communicate and prepare — before the first pass

Communicate — from your workbook: the PAN call to ATC, made as soon as the decision to land is made, and before the first pass. If things get worse in flight, upgrade to MAYDAY without hesitation.

Prepare — brief the passengers as in Lesson 17: brace position, harness security, what to expect.

Both are done before the first pass of the inspection — you shouldn't be making radio calls or briefing passengers while flying a low pass.

Precautionary Search and Landing — Theory

Waypoint 4 — Inspect

Precautionary Search and Landing — Theory
Precautionary Search and Landing — Theory

Join and the 500 ft pass

  1. Join on the normal crosswind at 1000 ft, trimmed for 80 kt — and make your PAN call to ATC and give your passenger brief before the first pass
  2. Downwind at 1000 ft — time the field from threshold to threshold
  3. Extend downwind, turn base wide of the field, and descend to 500 ft — wider than the low passes will be
  4. 500 ft pass — offset right of the landing path, time the field again, and assess WOSSSSET again from this new height. Then stay at 500 ft, configured, and fly the circuit at 500 ft
Precautionary Search and Landing — Theory

Timing the field

Fly trimmed at a steady 80 kt, and count the seconds from threshold to threshold — twice, on the 1000 ft downwind and again on the 500 ft pass. Then average the two — or read groundspeed from the GNSS and use it in place of averaging.

  • 1 kt is about 0.5 m/s, so 80 kt is about 40 m/s
  • 10 s ≈ 400 m
  • 20 s ≈ 800 m

Use groundspeed, not airspeed. The two timings are flown in opposite directions, so averaging them cancels most of the wind. If you have a GNSS, its groundspeed already includes the wind, so one timing at that groundspeed is enough.

You want at least 400 m for most small aeroplanes — but check your aircraft's manual for its short-field landing distance for the day.

Precautionary Search and Landing — Theory

Flying the low passes

  1. First low pass — 200 ft, slightly right of the intended landing path, level from threshold to threshold — check the surface, note drift, look for obstacles in the overshoot area. Apply full power two-thirds of the way along the runway, then climb back to 500 ft once past the far threshold and fly the circuit at 500 ft
  2. Second pass — 50–100 ft, again to the right, for a closer re-check — and again full power two-thirds of the way along the runway
  3. Repeat if you're not satisfied — then either fly the short-field landing, or go around and choose another field

Unlike a forced landing, you have power and time — keep the field in sight and use both to inspect properly before you commit.

Precautionary Search and Landing — Theory

Waypoint 5 — Land

Precautionary Search and Landing — Theory

Land — short-field revision

The approach was already flown as the last path of the inspection pattern — now the landing itself, the short-field technique from Lesson 22:

  • Full flap and a stable approach on the short-field profile
  • Minimum recommended speed crossing the boundary
  • Minimal float, then maximum braking
  • After landing: secure the aircraft, manage your passengers, and update ATS or other agencies of your situation if you're able to

If anything about the approach isn't right — go around. You have power; use it.

Precautionary Search and Landing — Theory

Waypoint 6 — Recap

Precautionary Search and Landing — Theory

Your turn — walk the whole sequence

Talk it through with the model as the field, saying each step out loud:

  • Decide — what's your trigger, and why now?
  • Configure — slow to a safe search speed, some flap
  • Select — apply the WOSSSSET criteria to choose a field
  • Communicate — make the PAN call
  • Prepare — brief your passengers
  • Inspect — walk the pattern: crosswind join, 500 ft pass, then the low passes — and time the field's length twice
  • Land — short-field technique, then secure the aircraft
Precautionary Search and Landing — Theory

Objectives check

Can you:

  • Describe the circumstances that call for a precautionary landing, and why decide early?
  • Configure the aeroplane for the search?
  • Apply the field-selection criteria to choose and inspect a field?
  • Describe the vital-actions sequence, including the PAN call and passenger brief?
  • Revise the short-field landing technique?
Precautionary Search and Landing — Theory

Arrival

Precautionary Search and Landing — Theory

Questions?

Any questions before the pre-flight brief?

This lesson trains the response to deteriorating conditions away from the aerodrome — weather, fuel, getting unsure of your position, or anything else the pilot isn't happy with — with the engine running throughout: deciding early, configuring the aeroplane, searching for and inspecting a field, and completing a short-field landing. It also assesses the pre-flight operational documents (MEL, NOTAMs, GNSS RAIM, ERSA, AIP) and revises short-field take-off and landing from Lesson 22. Confirm the pre-lesson workbook is done before starting — it covers the background/ factual material (why precautionary landings happen, turning illusions when flying low, fuel management and endurance, the pre-flight documents, the PAN call, and landing distance from the POH). This session builds on that rather than re-teaching it, and spends the live time on the judgement, the search, and the flying.

Run this as a poll. At each step, have students commit (hands, or write it on paper) before you reveal the next. Don't comment on the answers yet — keep a tally on the whiteboard if it helps. The debrief is on the "Which step?" slide.

Debrief against the tally. Expect "keep going a bit further" to have carried a lot of the room past step 2 — that's the lesson. Ask what at step 1 or 2 would have made deciding feel too early (embarrassment, get-there-itis, "it might clear"). Name those as the traps.

Height, fields, daylight, fuel and passenger calm all fall together as conditions deteriorate. The earliest part of the curve is where you have the most choice and the least cost. The decision is to make the call while you're still in the green zone. This diagram comes back at the recap.

Contrast directly with Lesson 17's hook: there, the trigger (engine failure) is unmistakable; here, the trigger is a judgement call the student has to make themselves. Stress that weather and fuel are only the classic examples — a fluctuating oil pressure or a sick passenger is just as good a reason to land early, and the same sequence applies. The trigger also shapes the real-life plan: a sick passenger or an engine indication argues for the nearest suitable field, quickly, while a deteriorating-weather scenario gives more time to search.

About 17 minutes total, leaving some headroom in the shorter 0.5 hr theory window (half the length of Lesson 17's). The waypoints follow the vital-actions sequence in order: decide and configure, search and select, communicate and prepare, inspect, land. Most of the factual/reference material (circumstances, turning illusions, fuel management, pre-flight documents, the PAN call) is already covered in the pre-lesson workbook — this session focuses on applying it: configuring the aeroplane, planning and flying the search, and the sequence that ties it together.

Click Direct-To to advance to Vital Actions.

Confirm the workbook was actually completed and clear up anything that didn't land before moving on. If it wasn't done, take a few extra minutes here to cover the workbook content verbally rather than skip it — the circumstances, turning illusions, fuel management, pre-flight documents and PAN-call material there is assumed known from here on. This also bridges Lesson 17: same discipline (decide early, fly the aeroplane first), different trigger — the engine is still running today, which is why there's power and time to fly a proper search rather than glide to a fixed point.

CASA A6.4(f-p): assess flight circumstances and decide, configure aeroplane for conditions, perform precautionary search procedure, select/inspect landing area, maintain orientation and visual contact, advise ATS, re-brief passengers, land and secure aircraft. NTS1.4/NTS1.5 underpin the sequence, as in Lesson 17. The discussion question is live — use the training area and route you'll actually fly today, not a generic answer.

CASA A6.4(g): configure aeroplane for conditions. FIM Ch 15: descend to a safe low cruise height and configuration once poor conditions are simulated. Reader instruction: check your aircraft type's recommended low-level search speed and flap setting before the flight.

Click Direct-To to advance to Search and Select.

FIM Ch 15: practise only in approved areas, avoid frightening livestock and annoying people, turning illusions caused by drift near the ground. CASA A6 4(o): low-flying hazards.

Click Direct-To to advance to Communicate and Prepare.

CASA A6.4(n,o): advise ATS or other agencies of situation and intentions; re-brief passengers about flight situation, brace position and harness security. PAN structure and PAN-vs-MAYDAY are workbook content (topic 5) — this is application, not re-teaching. The pattern on the next waypoint puts both before the crosswind join, so they are done while you still have height and time.

Click Direct-To to advance to Inspect.

Toggle each pass in the legend, or fly it with its play button, to talk through the pattern. Before any of this, the student has already selected the field against the Lesson 17 WOSSSSET criteria — including Shoots, the clear approach and overshoot paths — and this is the chance to confirm that choice from the air. The next three slides cover the join and 500 ft pass, how to time the field, and the low passes.

The crosswind join is labelled on the diagram as the point by which the PAN call and passenger brief must already be done — the student should not be making radio calls or briefing passengers while flying a low pass. If ATC isn't available, make the call on the area frequency or the CTAF as the operator's procedures require. Reassessing WOSSSSET on the 500 ft pass matters: the field looks different from circuit height than it did from the search height, and this is a low-cost chance to reject it before going lower. The 500 ft pass is deliberately wider than the later passes so the student has more of the field in view and room to turn away. The offsets and heights are illustrative — sanity-check the geometry against the diagram's rendered output, and against your own aircraft and training area, before using this live. After the 500 ft pass the aeroplane stays configured and the rest of the circuits are flown at 500 ft AGL, which is what CASA expects to see in training. Be clear that this is the practice standard: in a real event the height depends on why you're there — terrain around the field might argue for climbing back to 1000 ft, while a low cloud base might mean staying at or below 500 ft. Also tell the student that, once the problem is resolved, we will probably want to take off again from the same field, so the inspection should consider the departure as well as the landing.

Timing the pass is how the student works out the field's length (CASA A6.4(f): landing area length adequate for landing). The syllabus doesn't prescribe the method, so this is standard practice rather than a CASA element: fly trimmed at a steady 80 kt and count seconds threshold to threshold, twice — on the 1000 ft downwind and again on the 500 ft pass — then average the two. 1 kt is about 0.5 m/s (strictly 0.51), so 80 kt is about 40 m/s and the count multiplied by 40 gives a quick estimate in metres: 10 s is about 400 m, 20 s about 800 m. Remind the student the speed that matters is groundspeed. The downwind leg and the 500 ft pass are flown in opposite directions, so one has a tailwind (shorter time, field looks shorter) and the other a headwind (longer time, field looks longer) — averaging the two cancels most of the wind effect, which is the main reason for timing it twice. The GNSS groundspeed is an alternative to averaging: it already includes the wind, so one timed pass multiplied by the displayed groundspeed gives the length directly — still confirm the GNSS is serviceable and displaying groundspeed rather than airspeed. If the two timings disagree by much, fly another timed pass before trusting either. About 400 m is the usual minimum for most small aeroplanes, but the aircraft's own flight manual short-field landing distance for the day (with a margin) is the figure to compare against. Check that 80 kt suits your aircraft type's recommended search speed and configuration before the flight.

FIM Ch 15 background (structure only, not reproduced): descend to about 500 ft, simulate poor weather, choose a strip, fly over slightly to the right of the intended landing path at about 100 ft to check surface and drift and note obstacles in the overshoot area, climb to about 500 ft and circuit keeping the field in sight, fly a dummy approach again to the right for a re-check, repeat, then short-field landing or go-around. CASA A6.4(i): select landing area, carry out an inspection and assess its suitability — unobstructed approach and overshoot paths, landing area length adequate for landing, surface suitable for aeroplane type and clear of hazards. Full power two-thirds of the way along the runway is a safety margin on both low passes: the power is already in, so the aeroplane is set to climb away if a hazard appears or the aeroplane sinks, rather than relying on a late decision near the far end. It is not used on the timed 500 ft pass, because the extra power would change the speed before the far threshold and spoil the timing. The pass heights (200 ft, then 50–100 ft) and the ground track are illustrative — sanity-check the geometry against the diagram's rendered output, and against your own aircraft and training area, before using this live.

Click Direct-To to advance to Land.

Ask the student to talk through the short-field technique from Lesson 22 before you confirm or correct it — this is revision, not new teaching. A4.5 (short landing, level 2 — revision of Lesson 22's A4.5 level 3 standard). A6.4(p): land and secure aircraft and manage passengers. Go-around no lower than the operator's minimum height, as briefed.

Click Direct-To to advance to the recap.

Run this as a talk-through, with the 3D model on a desk as the field, or have the student walk the pattern themselves as "the aeroplane" while narrating. Hand over a scenario card (weather, fuel, position, an engine indication or a sick passenger) to start; the student calls out their sign to decide now. Every step should get a spoken answer. If the student skips one, that's the one to dig into. Replaces the two static summary-table slides with a hands-on recap that exercises the whole sequence, not just recall: the decision to conduct a precautionary search and landing, configuring the aeroplane, applying the field-selection criteria, the PAN call, the passenger brief, flying the inspection pattern (including measuring the field length), the short-field landing, and securing the aircraft.