Special VFR Offered into a Deteriorating Controlled Aerodrome
You are flying a dual cross-country with a PPL student from Palmerston North to Napier in a Cessna 172. Napier is controlled; the route crosses a mandatory broadcast zone. Forecast: cloud scattered at 1,500 ft, visibility 8 km, temporarily 1,200 ft and 5 km. The aircraft has 2 hours 10 minutes of fuel; the planned flight is 55 minutes, and you plan a 30-minute day VFR reserve. On arrival, Napier ATC reports visibility 3,000 m in drizzle and offers a special VFR clearance. The student is current but has no instrument experience and is anxious. The aircraft's transponder and radio are serviceable. You have a GPS but no instrument approach. There is a suitable uncontrolled aerodrome 20 minutes away with reported visibility 10 km and cloud at 3,000 ft. The student asks whether you can accept because the clearance is available.
1. Can you accept the special VFR clearance? Explain the VFR/SVFR meteorological and airspace requirements and your decision.
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Special VFR is not a general lowering of VFR minima; it is a clearance that permits flight within controlled airspace in specified SVFR conditions. You need an ATC clearance, must remain clear of cloud, and must meet the applicable SVFR visibility and cloud criteria. Reported visibility of 3,000 m may be above the 1,500 m figure often associated with SVFR, but that alone is not enough; you must also have flight visibility and cloud clearance that allow safe operation. You cannot accept simply because ATC offers it. The student has no instrument experience, the weather is drizzle, and the destination is below normal VFR. The safer decision is to divert to the uncontrolled aerodrome with 10 km visibility and 3,000 ft cloud, or return. Special VFR is a limited privilege in controlled airspace, not a tool for scud-running or for rescuing a bad destination decision.
2. How does fuel planning affect the decision, and what alternate should you consider?
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You have 130 minutes of fuel. The planned flight is 55 minutes, leaving 75 minutes. A 30-minute day VFR reserve leaves 45 minutes of contingency. If you divert to the 20-minute alternate, the plan becomes 55 + 20 + 30 = 105 minutes, leaving 25 minutes spare. That is workable on paper, but it assumes no holding, no missed approach, no vectoring and no second diversion. If you accept special VFR and then cannot land, the reserve erodes quickly. Fuel is therefore adequate for a clean diversion to the 20-minute aerodrome, but not for repeated attempts at Napier. The alternate with 10 km visibility and 3,000 ft cloud is the better choice; if that weather is doubtful, return to Palmerston North. Do not let the available clearance force a fuel-critical arrival.
3. What should you teach the student about ATC clearances and VFR into controlled aerodromes?
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Teach that an ATC clearance is an authorisation, not a guarantee of VFR conditions. The pilot remains responsible for see-and-avoid, terrain clearance and compliance with VFR minima. Before entering controlled airspace, obtain the clearance, read it back correctly and do not enter without it. If you cannot maintain VFR, say so and request an amended clearance or divert. A clearance does not override personal minima or the need for an alternate. Use the event to reinforce decision-making: set a go/no-go point before arrival, identify the diversion aerodrome and fuel plan, and brief what will happen if the destination weather is below VFR. The lesson is to stay ahead of the aircraft rather than negotiate with weather over the radio.