Aircraft Departure Downdraft

Right after takeoff-when were low, slow and heavy-is a lousy time to encounter convective activity.


Shortly after receiving my instrument rating, I had occasion to help ferry a Piper Archer a whole dozen miles. It was the dead of winter, dark, and snowing. The snow was dry and the temperature too low for it to stick to the Archer, itself cold-soaked. Even though I was as instrument-current as it gets, my comfort level was too low to tackle this. It promised to be a high-workload flight in conditions I had never experienced. I declined, and someone more comfortable with those conditions handled the flight uneventfully.

That was the first time a daunting instrument departure overcame my concern with an approach at the other end. But not the last. These days, in fact, Im usually a lot less concerned about an approach to minimums than I am a takeoff involving challenging weather.

An instrument departure into real weather can be the greatest challenge a pilot will face: The airplane is heavier than it will be at any other point in the flight, were at a low altitude and airspeed, and-while weve performed a thorough pre-flight-theres always the nagging doubt weve forgotten something. Sometimes, we can find ourselves taking off into weather poor enough that it prevents returning to the departure runway if we need to. Add to this mix a lack of subjective knowledge of how the weather will affect us, and the challenge of an instrument departure becomes much greater than an approach to minimums after a length of time “wearing” the airplane and the flight conditions.

For these and other reasons, an instrument departure can require more planning, more thought and more deference to the weather than an approach in similar conditions. As an example and presuming the same circumstances, I wouldnt have hesitated flying the Archer through an approach that dark, snowy night if Id been airborne for a while.

Pilots spend a lot of time agonizing over approaches. Thats as it should be, perhaps, but departures also demand our consideration. Just as we pick and choose routes, altitudes and destinations, we need to think about takeoffs and the weather-related risks they pose. Heres a good example of why.


On November 12, 2006, at 1125 Eastern time, a Piper PA-32R-300 Lance was destroyed when it impacted trees shortly after takeoff from the Williamsburg-Jamestown Airport (JGG) in Williamsburg, Va. The private pilot, with approximately 2200 hours, was seriously injured and the passenger was fatally injured. Instrument conditions prevailed; an IFR flight plan was filed for the flight to St. Petersburg, Fla.

The weather was flyable, but challenging. The automated observation at JGG, at 1120, included winds from 350 degrees at 16 knots, gusting to 24 knots. Visibility was five statute miles, with scattered clouds at 900 feet, a broken ceiling at 1400 feet and an overcast ceiling at 2100 feet. A nearby weather radar, at 1147, observed level 3 convective activity immediately west of the airport.

The pilot received an IFR clearance to St. Petersburg from a flight service briefer at about 1115. The pilot advised the briefer he would depart Runway 31 and was given a void time five minutes later.

The pilot later reported that, during the takeoff roll, he lifted the airplanes nosewheel off the runway early to “lessen ground drag on the nose.” He stated that “at VR and approximately 100 feet, airspeed started decreasing.” The airplane encountered a wind gust “of approximately negative 30 knots.” He had to increase the pitch angle in order to fly away from the ground. About this time, according to the pilot, the airplane was “hit from [the] top by wind.” The airplane subsequently impacted trees and was engulfed in flames.

According to two witnesses, as the airplane lifted off from the runway it was moving “abnormally slow,” and was “not climbing very quickly.” It then climbed a “short distance” before being “pushed down” about 10 to 15 feet. It then gained altitude, but did not climb above the height of the trees beyond the departure end of the runway. The airplane flew in a wings-level attitude straight into the tree line and moments later erupted in flames.


The airplane came to rest lodged in a tree about 1900 feet beyond the departure end of Runway 31, and about 40 feet above the ground. A majority of the airplane was damaged by fire. Both wings were intact, but both right wing fuel tanks and the inboard left fuel tank were burned. The left outboard fuel tank remained intact, and was full of fuel.

Examination of the flight controls did not reveal evidence of any pre-impact abnormalities. The flap handle was found in the 10-degree detent. Both main landing gear were in the down position; the nose landing gear was separated from the airframe. Both propeller blades exhibited S-bending and chordwise scratching indicating power was being developed. The fuel injector screen and fuel flow divider screen were absent of debris.

Probable Cause

The National Transportation Safety Board determined the probable cause(s) of this accident to include: “The pilots improper decision to depart into adverse weather conditions. Contributing was the gusty wind conditions.” Its easy for the NTSB to categorize the pilots takeoff decision as “improper,” given the outcome. But if the apparent downdraft hadnt developed at a critical time, Id be writing about something else this month.

The facts demonstrate the pilot knew the weather posed challenges for his departure and performed what he thought was an appropriate takeoff procedure. It might have been better to accelerate close to VY on the runway or in ground effect, retract the gear and flaps, then climb out rather than begin climbing at “VR,” an undefined airspeed in this class of airplane.

In the end, its not clear if the pilot knew convective activity was nearby or why he didnt wait for better conditions. More energy would have helped him fly out of the downdraft, which may have been a microburst. Although he knew he needed to modify his normal procedures, he may not have fully grasped the weathers effects and what might happen on encountering a downdraft/microburst at the wrong/right time.

Identical weather can be much more challenging when encountered during takeoffs and departures than when approaching and landing. Its often better to be on the ground, wishing you were in the air.


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