Going flying VFR under Part 91: Equipment and Weather

The weather minima, alternate rules, fuel and equipment carriage that used to live across a dozen documents now sit mostly in two: CASR Part 91 and the Part 91 Manual of Standards.

This article is the practical version of that. Not a walk through the regulations, but a walk through the question every pilot asks before a flight: am I legal to go? Four buckets: medical, aircraft and equipment, weather, personal minimums. It assumes you’re flying private VFR in an aeroplane under Part 91. We’llc over Part 141 training and commercial ops under Parts 121, 133 and 135 in future articles.

TL;DR - Am I Good to Go?

Medical. Class 2 (or Basic Class 2) for PPL. Class 5 self-declaration is now an option for day VFR private ops up to 2,000 kg MTOW, 10,000 ft, two on board, no aerobatics. RAMPC for the RPL pathway. Class 1 for CPL/ATPL commercial ops.
Aircraft. Day VFR aeroplane minimum equipment is sparse: ASI, altimeter, magnetic compass, clock. Radio in controlled airspace, at certified aerodromes, and for the low-level Class G “clear of cloud” alleviation. Mode S transponder if the aircraft has one fitted or was built or had its transponder replaced after the relevant date.
Weather. VMC minima depend on airspace and altitude. Default below 10,000 ft AMSL: 5 km visibility, 1,500 m horizontal and 1,000 ft vertical from cloud. Class G at or below the higher of 3,000 ft AMSL or 1,000 ft AGL: 5 km, clear of cloud, in sight of ground or water.
Alternates. Trigger for a VFR aeroplane is 1,500 ft ceiling and 8 km visibility at the destination across ETA minus 30 to ETA plus 60. Below that you need an alternate, or holding fuel (30 min for INTER, 60 for TEMPO). Day VFR within 50 NM of departure is exempt.
Fuel. Final reserve for a Day VFR piston single is 30 minutes.
Personal minimums. Set them above the legal minimums, write them down, don’t move them on the day. PAVE and IMSAFE are useful frameworks to define your minimums.

Medical

You need a current medical certificate or self-declaration appropriate to your licence and the operation. Five options matter for a private VFR pilot.

Class 1 is for CPL, MPL and ATPL holders, and required to exercise commercial privileges. Typically 12 months’ validity, less above certain ages. With a Class 1 being the highest level of certificate, you’re good to go for private flying.

Class 2 is the standard PPL medical, assessed by a DAME. Validity up to four years if you’re under 40, then shorter. It’s the most flexible certificate: CASA’s AvMed can manage conditions that the lighter options can’t.

Basic Class 2 is a simpler, cheaper pathway introduced under CASA EX69/21. Assessed by any GP who does commercial driver medicals, against the unconditional Austroads standard. Operational limits: private day VFR only, below 10,000 ft. The limits drop away if a Class 1 or Class 2 holder is in a control seat with command authority.

Class 5 is the self-declaration introduced on 9 February 2024 under CASA EX01/24. No doctor visit. You complete an online eLearning module via myCASA, self-assess against the published medical guidelines, pay $10, and the certificate is issued. Operational limits:

Day VFR only.
Maximum take-off weight 2,000 kg.
Maximum two persons on board (you plus one).
10,000 ft ceiling.
No aerobatics.
Australian-registered aircraft, within Australian-administered airspace.

Validity is five years if you’re aged 16 to 39, two years if you’re 40 to 74. You must carry a copy of the declaration while flying. You stop being eligible if your driver licence is cancelled on medical grounds, if you develop one of the disqualifying conditions, or if you start regularly using a disqualifying medication or substance. The list of excluded conditions is specific and worth reading before you apply.

RAMPC (Recreational Aviation Medical Practitioner’s Certificate) is the alternative for RPL holders. Single-engine piston, MTOW up to 1,500 kg, GP assessment against the Austroads standard. Class 5 has largely overtaken it for RPL ops because of the higher MTOW (2,000 vs 1,500 kg), but RAMPC still exists.

Practical advice: if you might progress to NVFR, IFR or commercial flying, get a Class 2 (or even a Class 1) from the start so you have a continuous medical history with CASA. If you’re a settled private pilot flying day VFR in a light single, Class 5 is cheaper and easier.

Aircraft and equipment

The legal equipment list for a Day VFR aeroplane is short. Part 91 MOS 26.10 mandates the fitment of these instruments to the aircraft; Table 26.06 sets out the minimum list. For a Day VFR aeroplane, you need:

Airspeed indicator.
Altimeter with an adjustable mb/hPa subscale, calibrated in feet.
Magnetic compass, either a direct reading compass or a remote indicating one with a standby direct reading compass.
A time instrument showing hours, minutes and seconds, fitted to the aircraft or carried by the pilot for the flight.

That’s it. No attitude indicator, no heading indicator, no turn coordinator, no VSI. You can legally fly Day VFR with nothing in the panel beyond ASI, altimeter, compass and a clock. Almost every certified aeroplane has a full six-pack plus a VSI because the type certificate requires it. But the Part 91 floor is sparse, which is why ultralight and RAAus-registered aircraft can legitimately fly with minimal panels.

Radio. Required for controlled airspace, for the low-level Class G “clear of cloud” alleviation near certified, military or other prescribed aerodromes, and for most CTAF operations. Detail sits in Part 91 MOS Division 26.5. In practice, plan as though a serviceable radio is required. The exceptions are narrow, and plus; why wouldn’t you carry one!?

Transponder and ADS-B. Airspace-dependent and has shifted in recent years. For VFR aeroplanes:

VFR ADS-B OUT is only mandatory at or above FL290, which a piston VFR aeroplane will never see.
Replacement transponders must be Mode S with ADS-B Extended Squitter capability, and new aircraft operating in Class A, B, C or E (or above 10,000 ft in Class G) must have one.

If you’re flying a typical training aircraft around Class D and Class G, you almost certainly already meet the requirement. If you’re unsure, ask your instructor or maintenance organisation.

ELT. When undertaking a flight more than 50 NM radius from the aerodrome of departure, you must carry a serviceable ELT. If the ELT is installed on the aircraft, it must be armed before flight. If it is a survival (portable) ELT it must be carried in a readily accessible place (Part 91 MOS 26.50). You don’t always need one, but if you fly a lot and your aircraft doesn’t have one fitted, I’d recommend getting a portable ELT for your flight bag.

Life jackets and survival kit. Over water beyond gliding distance from suitable land, life jackets must be readily accessible. Over remote areas, you need an appropriate survival kit. A genuine survival kit (water, signalling, first aid, shelter) beats a tokenistic one every time.

Oxygen. Required on board above FL125 (Part 91 MOS 26.43). Use requirements above 10,000 ft cabin altitude are also covered in Part 91 MOS 26.43. In a VFR piston single you’re rarely going above 10,000 ft, but if you regularly cruise at 9,500 ft a finger pulse oximeter is cheap insurance.

Beyond the legal equipment list, the aircraft also has to be airworthy: maintenance current, defects rectified or properly deferred, fuel and oil in spec, weight and balance within limits. The PIC carries that responsibility under CASR 91.215. If something is unserviceable, check the MEL (if one applies) or the placarding rules in CASR 91.150.

Weather

VMC: visibility and distance from cloud

The headline VMC criteria for a VFR aeroplane are in Part 91 MOS Table 2.07(3). Strip out the rotorcraft rows and you’re left with three bands and one Class D special case.

Where you’re flying	Visibility	Distance from cloud
Class C, D, E or G at or above 10,000 ft AMSL	8 km	1,500 m horizontal, 1,000 ft vertical
Class C, E or G below 10,000 ft AMSL, above 3,000 ft AMSL or 1,000 ft AGL (whichever is higher)	5 km	1,500 m horizontal, 1,000 ft vertical
Class G at or below the higher of 3,000 ft AMSL or 1,000 ft AGL	5 km	Clear of cloud, in sight of ground or water
Class D Control Zone	5 km	600 m horizontal, 1,000 ft above, 500 ft below

Class A is out of bounds for VFR without a CASR 91.045 approval, which the average private pilot will never need.

The third row is the one to think hardest about. The “clear of cloud, in sight of ground or water” relief exists because VFR pilots in uncontrolled airspace need to operate under cloud bases that occasionally drop below 1,000 ft AGL without becoming instantly illegal. In Australia, where weather rolls in fast and terrain is unhelpful, the relief is sensible.

It’s also exactly where pilots get killed. The “scud running” trap, drifting along under a lowering cloud base in 5 km visibility, is one of the most consistent contributors to controlled flight into terrain. Between 2015 and 2025 the ATSB recorded more than 100 VFR-into-IMC occurrences in Australian airspace, with roughly one in nine ending fatally. The pilots involved were almost never breaking equipment rules. They were operating at the legal minimum and finding out, late, that the legal minimum has no margin for surprises.

Special VFR

Special VFR is a separate clearance, not a relaxation of VFR. Under Part 91 MOS 2.01 it requires ATC authorisation, day only for aeroplanes, minimum 1,600 m visibility, and flight clear of cloud. ATC won’t offer it; you have to ask. They can’t vector you under SVFR except in an emergency, which means you’re still responsible for terrain and obstacle clearance in conditions where you might not see them clearly.

My take: if you’re a low-time PPL and the only way out of the CTR is to ask for SVFR, wait for the weather to improve. SVFR is a tool for instrument-rated pilots and experienced operators with very specific local knowledge. It’s not a workaround for being late. The ATSB report on the January 2025 Bankstown VFR-into-IMC occurrence (a student in a Piper Archer) shows how an SVFR request can become one link in a chain of decisions that ends badly. Worth reading in full.

Pre-flight weather planning

Part 91 MOS 7.02 requires the pilot in command to study the authorised forecasts and reports for the route, departure, destination and any planned alternate. If the information is more than an hour old at engine start, you have to get an update.

The forecast suite for a VFR aeroplane below 10,000 ft is GAF, GPWT for winds aloft, TAF or TAF3 for the destination and any alternates, METAR and SPECI for actuals, AIRMET and SIGMET, plus NOTAMs and area QNH. NAIPS is your one-stop. If anything looks marginal, look harder.

Alternates and the 30-minute buffer

The alternate minima for a VFR aeroplane (day or night) are 1,500 ft ceiling and 8 km visibility. Source: Part 91 MOS Table 8.08(1), Item 3.

If the destination forecast shows conditions worse than that during your arrival window, you need an alternate, or holding fuel. The arrival window runs from 30 minutes before ETA to 60 minutes after.

The “relevant weather conditions” that trigger the alternate requirement, from Part 91 MOS 8.04:

Cloud more than SCT below 1,500 ft.
Visibility below 8 km.
A 30 per cent or greater forecast probability of fog, mist, dust or anything else reducing visibility below 8 km.
Wind components outside the aircraft’s limits.
A thunderstorm, severe turbulence, or a 30 per cent or greater forecast probability of one.

Read that thunderstorm line carefully. A PROB30 TS in a TEMPO during your arrival window triggers the alternate requirement. The Part 91 MOS treats a 30 per cent probability of a thunderstorm the same way it treats a forecast of one.

The 30-minute buffer applies before and after the forecast adverse period. If a TEMPO for thunderstorms is forecast from 0400 to 0600 UTC, any ETA between 0330 and 0630 engages the alternate requirement. The buffer exists because weather doesn’t read its own forecast.

Part 91 MOS 8.04(6) lets you avoid nominating an alternate if you carry enough fuel to hold: 30 minutes for an INTER, 60 minutes for a TEMPO. Useful, but a real diversion is almost always better than burning fuel waiting for a weather window. Pre-decide the diversion on the ground.

Part 91 MOS 8.04(4): if you’re VFR by day within 50 NM of the departure aerodrome, the alternate requirement doesn’t apply. This is what makes local navs and circuit training practical. Not a licence to launch into anything, but it removes the alternate-planning overhead for a quick local flight.

Final reserve fuel

For a Day VFR aeroplane under 5,700 kg MTOW, final reserve fuel is 30 minutes at 1,500 ft above aerodrome elevation in ISA, at holding speed. Source: Part 91 MOS Table 19.02(2), Item 1. Night VFR and IFR step up to 45.

The build-up is: taxi + trip + alternate fuel (if required) + holding fuel for any INTER or TEMPO + 30-minute final reserve. Landing with less than final reserve is a fuel emergency: MAYDAY FUEL.

Thirty minutes is tight. Most instructors I respect quietly plan for 45 in a piston single, and an hour if there’s any chance of a hold or complication at the destination. The legal floor is 30. The sensible floor is more.

Personal minimums

Legal minimums are just that, minimums. They aren’t necessarily the operating standard you should follow.

A 100-hour PPL is not the same operational risk as a 1,500-hour CPL, and the regulations don’t distinguish between them. You have to do that yourself, in writing, before the flight. Personal minimums set above the legal floor, written down, and not moved on the day are a reliably effective intervention against VFR-into-IMC outcomes.

Two frameworks are widely used by organisations, instructors and are built into CASA’s safety material.

PAVE is the pre-flight risk picture: Pilot (currency, recency, hours in type, ratings), Aircraft (equipment, performance for the day, fuel, defects), enVironment (weather, terrain, airspace, time of day, surface), and External pressures (schedule, passengers, the people waiting for you at the destination). If two PAVE categories are showing marginal flags, the default is no-go.

IMSAFE is the personal pre-flight check: Illness, Medication, Stress, Alcohol, Fatigue, Eating and emotion. It’s deliberately short so you can run it every flight without thinking about it. Any one flag is a serious prompt to delay or cancel.

CASA has an excellent minimums checklist that you can use to get started on formulating your own.

For a newly minted PPL, sensible starting points are: ceiling at the destination at least 3,000 ft AGL, visibility at least 10 km en route, crosswind no more than 50 to 70 per cent of the AFM demonstrated component, wheels-down at least 60 minutes before last light, and 45 minutes of fuel on the ground instead of 30. Loosen those numbers one variable at a time as you build hours, and reset to conservative values after a break from flying.

Personal minimums deserve a full article and we’ll come back to them. The principle is simple: the rules tell you what’s legal, you tell yourself what’s wise. The no-go decision is the most underrated airmanship skill in light aircraft flying, and on the ground it’s free.

Night VFR has it’s own requirements

NVFR is technically VFR, but the rules diverge enough that it deserves its own treatment. The aircraft needs an attitude indicator, heading indicator, VSI, turn and slip, OAT, an approved GNSS or a ground-based nav aid (VOR or ADF), and full external lighting. Final reserve fuel goes up to 45 minutes. You generally need a destination alternate within an hour unless the destination has nav-aid support the aircraft can use, or you have an approved GNSS and you’re competent with it. The route minimum-height rules in CASR 91.277 add another layer. We’ll cover it properly in a future article.

References

Civil Aviation Safety Regulations 1998 (CASR) Part 91, particularly 91.045, 91.150, 91.215, 91.265, 91.267, 91.270, 91.275, 91.277, 91.280, 91.285, 91.455 and 91.810. legislation.gov.au
Part 91 (General Operating and Flight Rules) Manual of Standards 2020 (F2020L01514), especially sections 2.01 (Special VFR), 2.07 (VMC), 7.02 (weather study), 8.02, 8.04 and 8.08 (alternates), 19.02 (fuel), 26.06 (Day VFR equipment), 26.18 (radio), 26.43 (oxygen), 26.50 to 26.52 (ELT), and 26.67 to 26.70 (surveillance equipment). legislation.gov.au
AIP Australia, current issue: ENR 1.1, ENR 1.2, ENR 1.4, ENR 1.5 and ENR 1.7. Airservices Australia
CASA, Aviation medicals, including Class 5 medical self-declaration, Basic Class 2 and RAMPC. casa.gov.au
CASA Instrument EX01/24, Flight Crew Medical Status (Class 5 Medical Self-Declaration) Exemption 2024.
CASA, Plain English Guide to Part 91. casa.gov.au
CASA, Visual Flight Rules Guide (VFRG). vfrg.casa.gov.au
CASA Advisory Circular AC 91-15 v1.2, Guidelines for aircraft fuel requirements (October 2024).
Flight Safety Australia, “Probability and flight planning” (October 2023).
Flight Safety Australia, “Navigating the margins with Special VFR” (May 2025).
ATSB, AO-2025-003: VFR into IMC involving Piper PA-28, VH-BTN, Bankstown, and ongoing VFR-into-IMC investigation series.
Bureau of Meteorology, GAF and AIRMET User Guide. bom.gov.au/aviation

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