IFR Fix: Busting beneath the shelf

May 24, 2013

Sometimes it’s unavoidable: If you want to get where you’re going, you must file IFR. At other times, it’s a choice between convenience (VFR) and certainty (IFR).

Then how will you play it? One tactic is to file and cancel IFR if the weather holds up. But often it’s more convenient to just launch visually, and file in the air if necessary.

“If necessary” had proven unnecessary for a Cirrus SR22 cruising beneath 3,500-foot to 4,000-foot ceilings on an outbound IFR flight plan. So for the return flight later in the day, the pilot opted to proceed under VFR. In either case, the flight would likely be restricted below 3,000 feet because of the presence of an overhanging shelf of Class B airspace, the pilot theorized. Below the bravo airspace, there was an area of Class D airspace, but air traffic control had just cleared the flight through, at or above 2,500 feet.

A little tight. But with the pilot’s observation of ceilings along the partly overwater, partly overland route providing a precious pirep, could there be a cost for the convenience?

Only if something goes wrong.

Certainly, if two things go wrong.

“As I reached land the ceiling descended to just about 2,700 or 2,800 feet, so I descended to 2,500 feet but that still put me through the base of the clouds,” the pilot said in an Aviation Safety Reporting System filing that might cause other instrument pilots to examine the foundation of their “to file or not to file” decision making.

“Then ATC warned me about traffic ahead on a missed [approach] and suddenly I found myself trapped in and out of the clouds, unable to descend without busting the Delta airspace.”

Clouds prevented the VFR flight from spotting the traffic, “which was being called out by the traffic warning system as straight ahead.” Turning away brought the flight into the clear at the expense of a Class D airspace incursion, the pilot lamented in the ASRS submission, adding that it would have been better to monitor the ATIS broadcast over the ocean and ask for a clearance “when it was clear that I could not maintain VFR minimums.”

The experience also overhauled the pilot’s notions about risk management for a flight with tight constraints that could face changeable weather.

“Next time I will get the clearance first and cancel if the weather accommodates,” the pilot wrote.

Dan Namowitz

Dan Namowitz | Aviation Writer

Dan Namowitz is an aviation writer and flight instructor. He has been a pilot since 1985 and an instructor since 1990.