Not a member? Join today. Already a member? Please login for an enhanced experience. Login Now
Menu

BrownoutBrownout

by David Jack Kenny

Helicopters have a unique if limited ability to create their own weather. Those who fly them in even modest approximations of Arctic or desert environments learn that snow, sand, or dust kicked up by rotor wash can transform unlimited visibility into instant IMC, blinding the pilot to everything nearby. Worse, an aircraft flying a normal approach profile will outrun its own downwash until the final deceleration to a low-altitude hover, just when there’s least margin for error. A VFR pilot, or any pilot flying a VFR ship, risks losing control while attempting either to set the machine down or to escape to search for a less troublesome landing site. The chance of hitting the ground or some other obstruction makes horizontal acceleration out of the cloud a dicey proposition, so the best option is usually a near-vertical climb—if the pilot can maintain control for the few seconds necessary to rise up out of the obscuration.

The pilot of the Robinson R44 II that took off from Truth or Consequences, New Mexico, on a short sightseeing flight on August 31, 2013, could fairly be described as “experienced.” He held a helicopter instructor’s certificate with instrument instructor privileges and had logged more than 1,150 hours in rotorcraft, including 85 in the R44. The weather was ideal, with clear skies, light east winds, and pleasantly moderate temperatures, and the planned flight was simple: Take two passengers less than 15 miles south for an aerial view of the neighborhood in which one of them lived.

Four witnesses saw the helicopter settle into a hover across from the passenger’s house, only to be enveloped in a cloud of dust. It turned and began to move away at very low altitude, struck power lines, and crashed; the impact was hard enough to break two wooden utility poles. Two of the witnesses agreed that the helicopter flew underneath the wires but snagged them with its tail rotor. According to one, it actually passed safely beneath the lines before reversing course and flying below them again in the opposite direction. The main rotor severed the tail boom, and the resulting impact killed all three on board. Investigators found no evidence of any mechanical malfunction.

According to Robinson Helicopters, wire strikes are the leading cause of fatal accidents in their aircraft. It’s reasonable to expect that the pilot identified those power lines as a potential hazard when he reconnoitered the landing zone. Whether he lost track of their location when visbility deteriorated or simply forgot they were there will never be known, but the outcome reinforces the principle that climbing out of a whiteout (or brownout) is usually safer than trying to outrun it along the ground. Who knows what mischief lurks within the murk?

In many fatal accidents involving owner-flown aircraft, the NTSB never receives the required Pilot/Operator Aircraft Accident/Incident Report (Form 6120.1-2). In this case, the pilot did not own the helicopter, and its owner did submit the form. A block on page 9 solicits recommendations as to how the accident might have been prevented. The R44’s owner wasted no words: “Pay more attention?” It’s a recommendation that would serve all aviators well.