Study guide
4.3 Weather, Performance & Segregation Checks Before 5 m Ops
UK CAA A2 Certificate of Competency A2 CofC
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1 Introduction & A2 CofC Pathway
1.1 Exam Facts, Format, Pass Mark & Validity 1.2 Flyer ID, Operator ID & Practical Declaration 1.3 Operating Guides, Maintenance & Safe-to-Fly Decisions
2 Open Category Air Law
2.1 Open Category A1 / A2 / A3 & 2026 Near People Rename 2.2 VLOS, 120 m Height Limit & Flight Restriction Zones 2.3 Uninvolved Persons, Assemblies & Giving Way to Manned Aircraft
3 Near People Separation Rules
3.1 UK2/C2 Separation: 30 m Normal & 5 m Low-Speed Mode 3.2 Legacy Aircraft 50 m Separation & MTOM < 2 kg 3.3 The 1:1 Rule, Height vs Horizontal Distance & Safe Distances
4 Operational Ground Risk Mitigations
4.1 Site Selection, Segregation & Pre-Flight Briefing 4.2 Reacting to Approaching People & Abort Decisions 4.3 Weather, Performance & Segregation Checks Before 5 m Ops
5 Technical & Human Ground-Risk Mitigations
5.1 Prop Guards, Parachutes, Geo-Awareness & Other Technical Mitigations 5.2 Kinetic Energy, Mass, Speed & Ground Impact Risk 5.3 Medical Fitness, Alcohol, Medication & Fatigue
6 Aircraft Eligibility & Flight Characteristics
6.1 UK0, UK1 & UK2 Class Marks and A2 Eligibility 6.2 Rotorcraft, Fixed-Wing & Hybrid Operating Envelopes 6.3 Basic Principles of Flight, Stability & Control
7 Practical Procedures, Emergencies & Decisions
7.1 Flight Procedures & Basic Practical Drills 7.2 Emergency & Abnormal Procedures 7.3 Decision-Making, Customer Pressure & Occurrence Reporting
8 UAS Flight Performance Systems
8.1 Mass, Balance, Payload Effects on Performance 8.2 Battery Terminology, Types, Charging & Storage 8.3 Failsafe Modes, Return-to-Home & Lost-Link Behaviour
9 Navigation, Compass & Flyaways
9.1 GNSS Position Hold, Drift & Loss of Positioning 9.2 Compass Errors & Magnetic Interference 9.3 Firmware, Braking Distance & Flyaway Causes
10 Meteorology for Near-People Operations
10.1 Weather Sources, Reports, Forecasts & Local Assessment 10.2 Wind Speed, Gusts & Manufacturer Limits 10.3 Wind Gradient, Masking & Urban Turbulence 10.4 Temperature, Density, Precipitation, Visibility & Icing 10.5 Clouds, Cumulonimbus, Lightning & IP43
4.3 Weather, Performance & Segregation Checks Before 5 m Ops
Key Takeaways Explain This Topic AI
UAS.OPEN.030 allows reduction from the 30 m normal floor to a minimum of 5 m horizontal from uninvolved persons only when the manufacturer’s low-speed mode is active and the remote pilot has evaluated weather, UAS performance, and segregation of the overflown area.
Five metres is a privilege, not a default: if any of weather, performance, or segregation is unsatisfactory, remain at ≥30 m (UK2/C2 normal) or do not fly the close task.
A practical go/no-go checklist covers wind and gusts versus limits, visibility, battery and aircraft health, confirmed active low-speed mode, a clear buffer free of people and vehicles, pilot workload, and a viable abort path.
Low-speed mode must be the aircraft’s engaged function, not an informal impression of flying slowly; confirm the mode on the system before treating 5 m as available.
Even after a green checklist, apply 1:1 and reaction-time judgment—5 m is a legal floor, not a target height-agnostic spacing.
Last updated: August 2026
Why 5 m Needs a Formal Gate
For UK2 (and transitional C2-as-UK2) aircraft in A2 Near People operations, normal mode demands at least 30 m horizontal separation from uninvolved persons. The remote pilot may reduce that minimum to 5 m only when:
The active low-speed mode function is engaged , and
The pilot has evaluated weather conditions , performance of the unmanned aircraft , and segregation of the overflown area .
That structure is deliberate. Five metres leaves little time and space to correct mistakes. Kinetic energy is lower in low-speed mode, but wind, a tired battery, GNSS hop, or a person stepping from a doorway can still close the gap faster than a distracted pilot reacts. The A2 syllabus therefore treats the step-down as a conditional privilege , not the everyday A2 spacing.
Exam sentence to memorise: 5 m is allowed only with low-speed mode on and after weather + performance + segregation evaluation; it is never the automatic A2 distance.
Legacy sub-2 kg A2 aircraft do not get this 5 m package at all (Chapter 3): their person floor remains 50 m . Do not apply this section’s privilege to unmarked legacy types.
- The Three Evaluations (Regulatory Core)
- 1. Weather conditions
Ask whether the meteorological environment lets you hold position, stop, and move away from people inside a tight buffer:
Mean wind and gusts versus manufacturer limits and your personal minima (gust spread matters: 8 kt mean with 18 kt gusts is a different aircraft than 8 kt steady).
Wind direction relative to people, obstacles, and your abort path (downwind toward a path is worse than a breeze into open segregated ground).
Visibility and light — can you maintain VLOS and see approaching persons?
Precipitation, icing risk, temperature — performance and battery behaviour change; wet props and low temperatures cut margins.
Turbulence — mechanical turbulence near buildings can throw a slow multirotor several metres, which matters enormously at a 5 m floor.
If weather is borderline for a wide 30 m operation, it is failed for 5 m work. Tighten minima as you tighten separation.
2. UAS performance
Evaluate the actual aircraft state for this flight, not the brochure:
Mass and payload — near MTOM increases inertia and can worsen braking/response.
Battery health and state of charge — sag under load, cold packs, aged cells.
Control responsiveness, braking, and low-speed mode behaviour — does the mode engage correctly and cap speed as designed?
GNSS / position hold quality — multipath beside glass and steel can produce position jumps larger than 5 m.
Sensors, firmware, and known faults — prop damage, vibration, compass warnings, geo-awareness alerts.
Manufacturer data — never invent performance; if the manual warns against flight in current conditions, that is a no-go.
An aircraft that “usually flies fine” but shows GNSS yellow icons and a soft battery is not cleared for 5 m simply because low-speed mode can be toggled.
3. Segregation of the overflown area
This evaluation is the operational link to Section 4.1:
Is the ground area under and beside the flight path actually free of uninvolved persons?
Will it stay free for the duration of the close work?
What controls enforce that (barriers, timing, marshals, briefed involved-only zones)?
Are vehicles and animal traffic also managed? A car entering a courtyard can be as serious as a pedestrian.
If segregation is hope-based, the evaluation fails. Low-speed mode does not segregate a street.
Go / No-Go Checklist Before 5 m Ops
Use a deliberate checklist every time you intend to work inside the 30 m normal bubble. All items should be go before you treat 5 m as available; any no-go means stay at ≥30 m horizontal from uninvolved persons, relocate, or cancel the close task.
- Check Go No-go examples
- Class mark & privilege UK2 / transitional C2 + A2 CofC path Legacy only → 50 m floor, no 5 m package
- Low-speed mode Mode confirmed active on the aircraft/system “Flying gently” without mode; mode fault
- Wind / gusts Comfortably inside limits with margin Gusts near limit; rotor-turbulence alley
- Visibility / VLOS Clear view of UA and approach routes Fog, dusk glare, visual obstacles
- Battery / health Healthy pack, adequate %, no critical warnings Low %, swollen cell, persistent errors
Performance / hold Stable hover, crisp response, good GNSS Position hop, sluggish braking, heavy payload issues
- Segregation / buffer Clear buffer free of uninvolved people & vehicles Open public access, failed barriers
- Involved persons Briefed and in planned positions only Unbriefed “helpers” under the aircraft
Pilot workload Capacity for aircraft + people watch (spotter if needed) Solo pilot + complex cinema moves + busy edge
Abort path Clear lateral escape and contingency landing Only escape is over the public or into obstacles
1:1 judgment Planned horizontal ≥ max(5 m floor, height AGL, extra margin) Planning to sit at 5 m at 25 m AGL as a “target”
Worked go/no-go
Go example. UK2 multirotor, low-speed mode on and verified, 6 kt steady wind, full healthy battery, strong GNSS in an open private yard, fence locked, only briefed client inside a marked safe corner, pilot plus spotter, contingency grass pad into wind, task hover at 6 m AGL so 1:1 ≈ 6 m and you elect ~10 m from the fence line to uninvolved persons outside. Privilege may be used with continued monitoring.
No-go example A — weather. Mode on, but 15 kt gusting 25 kt between buildings. Evaluation of weather fails → remain ≥30 m or do not fly close; preferably postpone.
No-go example B — performance. Mode on, calm air, but GNSS unstable beside a glass atrium and the aircraft wanders. Performance/hold fails → open distance, land, or redesign.
No-go example C — segregation. Mode on, perfect aircraft, but a public footpath cuts 4 m from the planned hover and cannot be closed. Segregation fails → 5 m privilege unavailable.
No-go example D — workload. Everything physical looks good, but the pilot is alone, flying a complex orbit, talking to a client on the phone, and cannot scan for people. Workload/attention fails as an operational evaluation even if the regulation’s three words are “weather, performance, segregation”—professional application includes being able to act on what those evaluations imply.
Privilege, Not Default
Training and exam culture must fight the idea that “A2 means I always work at 5 m.” Correct framing:
Default mental model for UK2 A2: 30 m horizontal from uninvolved persons, no overflight.
Optional reduction: 5 m minimum after mode + three evaluations, still no overflight, still use 1:1 and extra margin as needed.
Any doubt: favour the larger distance or land .
Clients may push for close product shots. Your answer is the checklist, not their timeline. RAEs and theory questions reward the pilot who declines 5 m when segregation is soft.
Mid-Flight: Privilege Can Be Lost
Evaluations are not only a pre-take-off tick box. If conditions change:
Wind builds → open to ≥30 m or land.
Battery warning → leave the close volume; land with reserve.
Person enters buffer → Section 4.2 actions; re-evaluate whether 5 m remains justified.
Low-speed mode disengages or fails → you are back to normal mode floors immediately (30 m for UK2), not “approximately 5 m because I was careful.”
Build abort path thinking into the 5 m plan: know the direction of escape that increases horizontal distance from people without overflying them, and know the contingency pad that stays empty.
Linking Chapters 3 and 4
- Layer Content Role at 5 m
- Statutory floor 5 m min with mode + evaluations Hard minimum
- 1:1 rule Horizontal ≥ height AGL when that exceeds 5 m Often raises spacing above 5 m
- Site selection (4.1) Footprints, briefing, FRZs, contingency L Makes segregation evaluation true
- Reaction (4.2) Restore distance, no overflight, abort Handles evaluation failures in real time
- Technical mitigations (Ch 5) Prop guards, etc. May reduce harm but do not replace 5 m legal conditions
Technical mitigations never rewrite UAS.OPEN.030: prop guards do not alone unlock 5 m on a legacy airframe, and they do not replace weather or segregation checks on a UK2.
Memory Hooks for Section 4.3
Mode + weather + performance + segregation — all required for 5 m.
5 m = privilege, 30 m = default UK2 mental model.
Confirm mode engaged — not informal slow flight.
Checklist includes buffer clear, workload, abort path.
Conditions change → privilege ends; open distance or land.
Master this gate and you connect air law numbers to the operational and technical ground-risk story the A2 CofC exam is built to test.