IFR Fix: 'One vicious bundle'

June 7, 2013

If a VFR pilot’s worst nightmare is to blunder into solid clouds, armed only with basic instrument flying skills, a similarly scary scenario awaits the instrument pilot who bets on sneaking through a stormy sector, and loses.

Some pilots, flying aircraft fortified with information technology and systems, have become emboldened to push into conditions they wouldn’t challenge in a less-capable aircraft, completely missing the point that their new equipment was not intended as a dare.

Others taunt the tiger by flying uninformed into areas where convective activity is developing, figuring on squeezing between the most diminutive-looking cells.

But you can’t judge a thunderstorm by its silhouette.

“A thunderstorm packs just about every weather hazard known to aviation into one vicious bundle. Turbulence, hail, rain, snow, lightning, sustained updrafts and downdrafts, and icing conditions are all present in thunderstorms,” cautions the Instrument Flying Handbook.

That’s also true many miles away from the cell.

So, the next time you hear ATC granting aircraft permission to “deviate as needed,” tune in the nearest HIWAS broadcast and learn what’s up. If an aircraft up ahead is asking ATC for a block altitude clearance, tighten your seatbelt, listen up, and slow down.

On Sept. 15, 2006, the nightmare came true for two occupants of a Cirrus SR20 that crashed near Maybell, Colo., while en route in visual conditions from Tooele, Utah, to Lincoln, Neb. The pilot had air-filed IFR and been advised of airmets for obscuration, turbulence, and icing. He was advised to contact Flight Watch for more information.

An hour later, the pilot told Denver Center that the aircraft was accumulating ice and unable to maintain 14,000 feet as assigned. A block altitude from 12,000 feet to 13,000 feet was issued. The aircraft’s final transmission reported “serious” icing and inability to maintain 12,000 feet.

The National Transportation Safety Board reviewed weather data including Doppler radar scans, concluding that the Cirrus “was in the immediate vicinity of a 35 dBz cell when the pilot first reported icing conditions.” The higher the dBz number on a 0-to-75 scale, the heavier the precip.

The pilot’s failure to obtain a weather briefing, the thunderstorm, ice, loss of control, and not deploying the SR20’s airframe parachute were given as probable causes of the accident—one that could exemplify any IFR pilot’s worst nightmare.

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.