FAIRFIELD, NJ, USA
N8041J
Robinson R-22B
The student pilot was receiving dual instruction in the helicopter in atmospheric conditions conducive to carburetor icing. A 'straight-in autorotation with power recovery' was entered with only partial carburetor heat applied. When throttle was applied for the power recovery, the helicopter experienced a total loss of engine power. The flight instructor said the engine and rotor RPM decayed simultaneously and the helicopter suffered a hard landing. According to the Pilot Operating Handbook, full carburetor heat was to be applied during autorotation. After the accident, the flight instructor reported there were no mechanical deficiencies with the helicopter and the engine started and ran on the airframe.
On January 15, 1999, at 1538 eastern standard time, a Robinson R-22B helicopter, N8041J, was substantially damaged during a simulated forced landing to the Caldwell Essex County Airport (CDW), Fairfield, New Jersey. The certificated flight instructor and student pilot were not injured. Visual meteorological conditions prevailed for the local instructional flight that originated at CDW, approximately 1420. No flight plan was filed for the flight conducted under 14 CFR Part 91. In a written statement, the CFI said: "Having already flown 1.2 hours dual training, we initiated a straight-in autorotation to power recovery on runway 22. We entered as usual at 1200 feet indicated, speed 65 knots indicated, and carb heat applied. On the way down we kept the engine rpm around 80 %, rotor rpm in the green, and speed between 60 and 70 knots. At the end of the flare we leveled the ship out at about 7 feet agl (above ground level) with about 20 knots speed. "In the process of rolling on the throttle to join the needles and bring back in the power for the hover, I noticed no engine response and saw both rpm (engine and rotor) decaying simultaneously. I was not able to recover any rpm, and we did a hard landing on the runway. I suspect carburetor icing, with the engine dying when we rolled the throttle on to bring back the power." In a separate written statement, the CFI stated: "...just before entering autorotation I noticed a carburetor temperature of 15." According to a record of telephone conversation from the FAA inspector: "[The CFI] stated that during the flight he utilized partial carburetor heat to maintain the Carburetor Air Temperature (CAT) above the yellow segment of the gauge. He stated that just prior to commencing the autorotation, he applied slightly more carburetor heat and then observed the CAT above the yellow segment on the gauge, at approximately 15 degrees. He does not recall if he applied full carburetor heat prior to reducing power to approximately 80% and commencing the autorotation..." According to the normal procedures section of the Robinson R-22 Pilot Operating Handbook, "USE OF CARBURETOR HEAT" was as follows: "During autorotation or reduced power below 18 inches MP [manifold pressure] apply full Carb Heat regardless of cat gauge temperature...CAUTION: CAT gauge is only effective above 18 inches MP." According to the Robinson R-22 Flight Training Guide, the power recovery portion of the autorotation is performed as follows: "At approximately 8 to 10 foot skid height, begin to level the helicopter with forward cyclic...As the RPM needles join, it may be necessary to add throttle to achieve a hover." According to the emergency procedures section of the Robinson R-22 Pilot Operating Handbook, the responses to "POWER FAILURE BELOW 8 FEET AGL" were as follows: 1. Apply right pedal to prevent yawing. 2. Allow rotorcraft to settle. 3. Increase collective just before touchdown to cushion the landing. The FAA Inspector examined the helicopter at the operator's facility on January 25, 1999. In a telephone interview, the Inspector stated the examination revealed no pre-impact anomalies. Flight control continuity was established and the engine started and ran on the airframe. Weather reported at CDW, at 1545, was measured ceiling 2,000 feet broken, with winds from 250 degrees at 8 knots. The temperature was 32 degrees and the dewpoint was 32 degrees. According to an icing probability chart published by the FAA, atmospheric conditions were conducive to "...serious icing at cruise power."
The flight instructor's failure to maintain rotor rpm and his failure to complete the autorotational descent. A factor in the accident was the flight instructor's failure to fully deploy carburetor heat as directed in the Pilot's Operating Handbook.
Source: NTSB Aviation Accident Database
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