VFR Clearance Near High Terrain with a Failing Radio
A VFR pilot in a Cessna 182 plans Port Moresby Jacksons to Kerema via the coast. The aircraft has a serviceable Mode C transponder, but the pilot's VHF radio has intermittent transmission; reception is good. Cloud base is 1,800 ft, visibility 8 km, and the route briefly enters controlled airspace around Jacksons. The pilot requests a special VFR clearance to depart through the control zone and then remain VFR. The tower advises that special VFR is not available because of IFR traffic, but offers a VFR clearance with a 1,500 ft altitude restriction and a requirement to remain clear of cloud. The pilot is not instrument rated. The pilot's planned track would take the aircraft within 2 NM of high terrain at 2,300 ft. The pilot asks whether the clearance can be accepted and what to do if radio failure occurs after departure.
1. Can the pilot accept the tower's VFR clearance with the 1,500 ft restriction? Address VFR minima, terrain clearance and special VFR.
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The pilot cannot simply accept the clearance because it is offered. Special VFR is not available, so the flight must remain VFR. In controlled airspace, VFR requires the prescribed flight visibility and cloud separation. With a cloud base of 1,800 ft, a 1,500 ft restriction leaves only about 300 ft below cloud, which is marginal and may not satisfy the vertical separation requirement.
More decisively, the planned track passes within 2 NM of terrain at 2,300 ft. At 1,500 ft the aircraft would be below the terrain, so the clearance is unsafe and cannot be accepted on that route. The pilot should request a higher altitude, a different route clear of terrain, or delay until conditions allow a safe VFR profile. The pilot is not instrument rated, so there is no option to accept an IFR clearance or enter cloud. An ATC clearance does not relieve the pilot of terrain clearance responsibility.
2. What should the pilot do if the radio fails after departure, and what should be done before departure to reduce risk?
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Before departure, the pilot should have the radio fault checked, carry a backup radio or mobile phone if available, obtain a clearance that does not depend on continuous communication, and nominate a route and altitude that remain clear of controlled airspace and terrain.
After a radio failure, the pilot should squawk 7600, continue under VFR, remain clear of controlled airspace unless a previously received clearance explicitly covers the route, and land at the nearest suitable aerodrome. The pilot should not press on into IMC or descend below safe terrain clearance to remain VFR. After landing, notify ATC as soon as possible. If the failure occurs before entering controlled airspace, the safest action is to stay outside and return or divert. The key judgement is that a clearance is not a substitute for see-and-avoid and terrain separation.