N106LN

HISTORY OF FLIGHTOn June 7, 2013, about 2140 central daylight time, N106LN, a Eurocopter AS 350 B3 helicopter, impacted terrain and came to rest on its side at the Grand Prairie Municipal Airport (GPM), near Grand Prairie, Texas. The two pilots sustained minor injuries. The helicopter sustained substantial tailboom damage. The helicopter was registered to CFS AIR LLC, Danbury, Connecticut, and was operated by Air Methods Corporation, Englewood, Colorado, under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Night visual flight rules conditions (VFR) prevailed for the flight, which did not operate on a VFR flight rules flight plan. The local flight originated from GPM about 2111.

According to the instructor pilot, they were performing a "simulated" hydraulics failure maneuver. On shallow approach, he told the pilot under instruction to fly the helicopter to a designated point at which they would do a "go around." The instructor pilot, in part, stated:

As the pilot got down to approximately 3-5 feet, we were getting a little

slow I again mentioned that we go around. We were at that time, on

the left side of the runway. As the pilot started increasing the power,

the nose started coming up and I told him to get the nose down so the

airspeed would increase. He also said it was hard to apply right pedal,

so I came on the controls with him to assist because by this time, the

aircraft was starting to turn left of runway heading. As I applied forward

cyclic, I think that we may have overcompensated and when the nose

started coming down past level attitude, I felt the pilot was applying aft

cyclic feeling that he was going to be too much nose down, which we

were. Again, I made an input to get the aircraft level. The aircraft

started spinning more to the left, and we were experiencing more

extreme pitch attitude changes and not climbing. I think that I had

told him to turn the hydraulic switch back on and I don't know if he was

able to do that or not. At some I point, I noticed that the aircraft was

positioned in the water retention basin and I saw that we might be

heading toward an rv park nearby. At this point, I just tried to get the

aircraft level and since the right pedal input to correct the left spin, I

reduced the power to at least slow the rotation down. I saw the ground

coming up rapidly and applied power again to cushion the landing as

much as possible. We impacted the ground and rolled over on our right

side.

According to the pilot under instruction, the helicopter departed GPM's runway 35 and entered left closed traffic. The pilot under instruction, in part, stated:

After a climb to 1200 [feet] and 80 [knots] the check airman initiated

simulated hydraulics off, by depressing the hydraulic test switch. I

slowed the [helicopter] to 60 [knots] and moved the collective hydraulic

switch to the off position. I turned base to final for a low approach

adjusting the airspeed and altitude as necessary arriving over the

runway, intending to touch down at, or just above [effective

translational lift]. The check airman asked if I thought I could land safely

and I answered yes. He said, "Okay let's go around." When I applied

power and pushed the nose over to gain airspeed the helicopter yawed

approximately 45 degrees left and the nose tucked slightly. I added

more right peddle but was unable to correct the yaw. As we proceeded

to the left margin of the runway, I added right cyclic. This made the

aircraft crab right, but the nose continued to yaw left. At about 90

degrees to the runway, the check airman got on the controls as we

began a rapid series of turns to the left, each revolution faster and more

violent than the last, until impacting sloping terrain just west of the

runway. The aircraft landed left skid high on the slope, and rolled on its

right side facing southeast. PERSONNEL INFORMATIONThe instructor pilot, age 64, held a Federal Aviation Administration (FAA) commercial pilot certificate with rotorcraft-helicopter and instrument helicopter ratings. He held a flight instructor certificate with helicopter and instrument helicopter ratings He held a second-class medical certificate with no limitations, which was issued on October 17, 2012. The operator's accident report indicated that the pilot accumulated 10,550 hours of total flight time and 1,851 hours of flight time in AS350 helicopters. The operator reported that the pilot accumulated about 75 hours of flight time in the 90 days prior to the accident, 32 hours within the 30 days prior to the accident, and 4 hours in the 24 hours prior to the accident. The pilot received his most recent flight review on January 14, 2013. Subsequent to the accident report, the operator further outlined the instructor pilot's flight time since April of 2008 to July 9, 2014, as:

AS350 B 5+00 hours

AS350 BA 10+26 hours

AS350 B2 282+10 hours

AS350 B3 205+05 hours

The pilot under instruction, age 66, held a FAA commercial pilot certificate with rotorcraft-helicopter and instrument helicopter ratings. He held a second-class medical certificate with no limitations, which was issued on November 21, 2012. The operator's accident report indicated that the pilot accumulated 9,511 hours of total flight time and 76 hours of flight time in AS350 helicopters. The operator reported that the pilot accumulated about 18 hours of flight time in the 90 days prior to the accident, 1 hour within the 30 days prior to the accident, and 1 hour in the 24 hours prior to the accident. The pilot received his most recent flight review on June 8, 2012. Subsequent to the accident report, the operator further outlined the pilot's flight time since April of 2008 to July 9, 2014, as:

AS350 B2 2+25 hours

AS350 B3 119+31 hours AIRCRAFT INFORMATIONN106LN was a 1999 model Eurocopter AS 350 B3 helicopter with serial number 3251. It had a replacement FAA airworthiness certificate issued on March 28, 2000. According to the operator, the helicopter's most recent maintenance inspection was completed on June 6, 2013. The helicopter accumulated 7,682 hours of total time on that date. Its maximum gross weight was 4,961 pounds. The helicopter was powered by a Turbomeca Arriel 2B engine, serial number 22036, which was rated at 747 horsepower for takeoff and 728 horsepower for continuous operations. The operator reported that at the time of the accident, the helicopter's weight and balance was 4,355 pounds and its moment arm was at 135.9 inches from its datum, which were both within limitations.

According to NTSB report LAX05LA025, on November 2, 2004, N106LN experienced a partial power loss after takeoff followed by a hard landing. The helicopter's tailboom was substantially damaged and a major repair and alteration form, dated April 1, 2005, approved its tailboom's repair. METEOROLOGICAL INFORMATIONAt 2135, the recorded weather at GPM was: wind 040 degrees at 4 knots; visibility 10 statute miles; sky condition clear; temperature 24 degrees C; dew point 11 degrees C; altimeter 29.93 inches of mercury. AIRPORT INFORMATIONN106LN was a 1999 model Eurocopter AS 350 B3 helicopter with serial number 3251. It had a replacement FAA airworthiness certificate issued on March 28, 2000. According to the operator, the helicopter's most recent maintenance inspection was completed on June 6, 2013. The helicopter accumulated 7,682 hours of total time on that date. Its maximum gross weight was 4,961 pounds. The helicopter was powered by a Turbomeca Arriel 2B engine, serial number 22036, which was rated at 747 horsepower for takeoff and 728 horsepower for continuous operations. The operator reported that at the time of the accident, the helicopter's weight and balance was 4,355 pounds and its moment arm was at 135.9 inches from its datum, which were both within limitations.

According to NTSB report LAX05LA025, on November 2, 2004, N106LN experienced a partial power loss after takeoff followed by a hard landing. The helicopter's tailboom was substantially damaged and a major repair and alteration form, dated April 1, 2005, approved its tailboom's repair. WRECKAGE AND IMPACT INFORMATIONThe helicopter came to rest on its right side in the grass infield on the west side of runway 35 about 1,000 feet from the runway's threshold. The main rotor blades exhibited varying degrees of damage consistent terrain impact. The cowling over the rotor mast was deformed and torn. The left side, as viewed from aft looking forward, fuselage and tailboom near their juncture exhibited areas of buckling. A semicircular opening was torn in the cowling covering the tail rotor driveshaft about a foot aft of the tailpipe exhaust heat shield. Skid-width indentations were noted in the grass infield surface near the wreckage.

FAA representatives, party members, and technical advisers examined the wreckage on-scene and during follow-up examinations. The engine and its main rotor gearbox remained attached and were located within the fuselage structure. Flight control continuity was traced and all observed separations were consistent with overload. The hydraulic system was supplied hydraulic pressure and no leaks were noted. The hydraulic system, including the three main rotor servos, accumulators, and tail rotor servo and yaw load compensator, functioned when tested. ADDITIONAL INFORMATIONThe FAA Helicopter Flying Handbook described effective translational lift. The handbook, in part, stated:

While transitioning to forward flight at about 16 to 24 knots,

the helicopter goes through effective translational lift (ETL).

... Between 16 and 24 knots, the rotor system

completely outruns the recirculation of old vortices and

begins to work in relatively undisturbed air. The flow of

air through the rotor system is more horizontal; therefore,

induced flow and induced drag are reduced. The AOA is

effectively increased, which makes the rotor system operate

more efficiently. This increased efficiency cont...