Trapped

Trapped is an ominous sounding word. Being trapped above cloud can be down right frightening. VFR over the top is legal as long as we follow the rules and use caution. In the mountains, it is often safer to fly VFR OTT than to scud run under the cloud. Safer, that is, if we do not allow ourselves to get trapped above cloud.

The PA 28-140 pilot departed Lawrence, Maine for Bromont, Que., at 1230Z. As he approached Bromont above cloud at 8,500 feet, he was unable to descend VFR. He diverted toward Sherbrooke, but still was unable to descend VFR. His last contact was with Montreal Centre at 1505Z when he was 12 miles south of Sherbrooke at 8,000 feet. He was directed to contact Boston Centre for further assistance, but he never made the call. Montreal Centre noticed the aircraft descending rapidly and then lost radar contact near Mount Hereford. A search was immediately initiated. The aircraft was located the next day. The pilot did not survive.

The Transportation Safety Board reported that the aircraft impacted the ground at a 65 degree angle with engine developing power. The Montreal radar plot indicated the pilot descended from 8,900 feet to 8,300 feet, turned left, continued descending, and disappeared from radar. The weather at Sherbrooke at 1600Z was 27009KT 9SM BKN024 OVC036 02/00 A2958 CF5SC3.

A Mooney 20 pilot en route from Swan River to Andrews, Man., contacted St Andrews Tower to report that he was above cloud at 15,000 feet. He was sent to Winnipeg Centre, to whom he reported he was unable to descend VFR and was unable to accept an IFR clearance. He also reported he had plenty of fuel, but no oxygen. The Centre Controller vectored the pilot 20 miles north of Winnipeg where other aircraft had reported breaks in the cloud. The Mooney pilot then descended VFR and landed at St Andrews. The pilot later reported that the weather was worse than forecast and that he had to climb to stay above the cloud. He understood that he had entered Winnipeg Terminal Control Area above 12,500 feet without a clearance.

An American Aviation AA 5 advised Vancouver Terminal that he was over the Georgia Strait west of Vancouver VFR above cloud. The Vancouver Terminal Controller vectored the AA 5 south, where the pilot found a break in the clouds, descended VFR, and eventually landed at the Langley Airport.

Planning and pilot mindset appear to be the problems in all of the cases described. Careful weather planning is important to safe VFR over the top flight. The regulations require that you climb clear of cloud and maintain 1,000 feet vertical distance from cloud. The vertical distance between layers of cloud must be at least 5,000 feet and the flight visibility must be at least five miles for the en route portion of the flight. The destination must be forecast to have a maximum of scattered cloud, five miles visibility, no precipitation, no thunderstorms and no blowing snow. The forecast conditions for the destination must be forecast to exist for one hour before the planned ETA to two hours after the ETA if a TAF is being used, and for one hour before the planned ETA to three hours after the ETA if a GFA is being used.

It is possible for cloud to go from forecast scattered to overcast during a flight, but it isn’t likely. More likely, the cloud in the above scenarios was overcast or broken at the destination and did not improve as forecast. Departing with this scenario is taking a chance. If a departure is made, regular weather updates must be requested. Weather seldom breaks open instantly. It takes time. If the weather has not showed an improvement by two hours before the ETA it might be a good idea to return to the departure airport. This assumes that the departure was not through a small hole in the cloud.

Pilot mindset is also important. If we depart with the idea the weather will improve as forecast, we will continue despite the lack of improvement at the destination and like the Mooney pilot, we will likely continue despite the rising cloud under us. The Mooney pilot continued despite the lack of supplementary oxygen and the fact he climbed into IFR airspace without a clearance.

For all flights where the weather has the slightest significance, we must have the mindset that we might not make it to the destination. This mindset will help us make a decision to divert or turn around before we get into trouble.

VFR over the top is a safe alternative with planning and a cautious mindset. Don’t depart through a small hole unless you know for sure there is an airport nearby you can successfully divert to if something goes wrong. Be cautious about departing for a destination where the weather is below the VFR over the top requirements, but is expected to improve, unless it is already showing signs of improvement. Even then, check the current conditions at the destination at least hourly, and be ready to turn around.

Study the GFA for the en route weather and talk to a weather briefer. If there is any instability in the weather system covering the en route portion of the flight, there is the possibility the cloud tops will increase in height over the planned route, or imbedded towering cumulus will develop.

If there is any doubt about maintaining legal altitudes, or about the length of time flight above 10,000 feet may have to be maintained, don’t go or turn around.

The PA 28-140 pilot crashed in a manner consistent with a spiral dive. Why control was lost we will never know. Maybe he entered cloud and became disoriented. Maybe he became disoriented in his panic to find a hole in the clouds. The Mooney pilot was lucky he didn’t meet the same fate. He very easily could have become hypoxic.

We must always leave ourselves a way out. If we don’t, we will set the trap. If we persist blindly, we will almost surely trip the trap. ATC may not always be able to help us slip out of it.

Dale Nielsen is an ex-Armed Forces pilot, charter pilot and air service operator. He lives in Richmond B.C. where he freelances as an aerial photography pilot and Class 1 flying instructor. Nielsen is also the author of five flight training manuals published by Canuck West Holdings.