Sud SA 318C N318DB

Summary

On 8 May 2013 at about 13:13 local time, a Sud SA 318C registered N318DB, operated by Mile HI Inc, was involved in an accident near South Bay, Florida, United States. 4 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

8 May 2013 at 13:13

Classification

Accident

Location

South Bay, Florida, United States

Coordinates

26.4439, -80.8711

Aircraft

Sud SA 318C

Registration

N318DB

Category

Helicopter

Year built

1968

Engines

1

Operator

Mile HI Inc

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Weston → Weston

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA13LA242

Nobody was injured.

The pilot’s failure to maintain proper rotor rpm while hovering in sideways flight.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

During a deer population survey flight over swampy terrain, the pilot descended the airplane from 200 feet to a hover about 25 feet above ground level and then side-stepped the helicopter right to maneuver over an island. As he did so, the helicopter began to yaw right and descend. The pilot corrected the yaw and increased collective pitch; however, the helicopter continued to descend. He then moved the cyclic forward in an attempt to fly through effective translational lift, but the descent continued, and the helicopter impacted the swamp and came to rest on its right side. Examination of the wreckage revealed that the helicopter had adequate fuel and was about 400 pounds below its maximum gross weight. No evidence of any preimpact mechanical malfunctions were found that would have precluded normal operation. However, the examination did reveal that the main rotor pitch angle cockpit indication was at 20 degrees (16 degrees when power was applied), which was beyond the redline of 15 degrees. The helicopter would have required more power to hover in sideways flight, below effective translational lift, than it would have required for a stationary hover. One of the common errors in hovering sideways flight is the failure to maintain proper rotor rpm. The excessive main rotor blade pitch angle and the pilot's report that the helicopter continued to descend after he increased the collective pitch and that he had to correct a right yaw indicate that it is likely that he failed to maintain proper rotor rpm during the hovering sideways flight.

Quoted verbatim from the NTSB record.