Fraught with the risk, a scud running pilot conducting a flight that started out under VFR may blunder into IMC conditions. The outcome is known as and described by the catchphrase continued VFR.
In a foray to get across the Sierra my hope was to have a “look-and-see” as it was obvious from official reports as well as my observation on the ground from the flat valley floor that mountain tops were likely to be obscured. My plan was to depart and follow the North Fork of the San Joaquin which would traverse the range and lead to the Mammoth Pass. At 9,300 ft. elevation this is the lowest point at the ridge for over 250 miles. I’d crossed there many times during routine visits to the MMH airport so I knew it visually. But today it wasn’t visible from start. I launched pretending that there’d be a break in the clouds as a possibility.
There’s the option to fly VFR over-the-top [of the clouds] but this assumes the there will be a clearing or at least a hole to descend through at point B. My Centurion P210N, while very capable altitude performance wise was ill-equipped for an in-cloud icing conditions encounter so I elected to stay underneath the deck.
Barreling up the North Fork canyon it was apparent that the cloud ceiling was solid. However, I still met separation criteria from both cloud and terrain so I pressed onward. Emotional stress began to factor in. The hope for a light at the end of the tunnel was not assured and further the undercast was a grey mass. In fact, to the left and the right was plenty gloomy with the canyon walls merging with cloud. I routinely swung my vision to assess. The Centurion has a back window and this scan included looking behind to verify that my completed route was still re-traceable. I found myself becoming increasingly concerned, not so much with what was ahead, but what was behind. I was relying upon a 180 degree turn route escape. That backup was becoming less assured as I pressed forward.
Canyon flying presents the peril of getting boxed in meaning U-turn collision with canyon wall. Further, that lovely diminishing tight circle of clear daylight aft was becoming quite small. Maintaining visual with the mountainous terrain was crucial and going IMC at this juncture could not be good at all. The grey tunnel surround was bleak.
I learned about flying from this. The trap of continued VFR was raring to bite. Finding relief and dumping the anxiety, I aborted and turned back.
If you don’t like the mountain weather – wait a few minutes (hyperbole). I returned to base for re-fuel and flew an alternate mission plan. All the wiser, this was the safe course and a successful outcome. Discounting expectation bias will help a pilot to avoid a continued VFR pitfall.