The NTSB recommends that the FAA:

Issue a flight standards information bulletin (FSIB) informing operators and pilots of single-engine helicopters equipped with Rolls-Royce Model 250 series IV engines of the circumstances of this accident and indicating that a potential fault with the full authority digital electronic control system may cause a sudden, uncommanded decrease of engine power without any identified cockpit indication or warning. The FSIB should also note that switching to manual mode may correct the engine power problem but that recovery to full power may take 2 to 6 seconds, thus possibly precluding a successful recovery to normal flight while operating in those altitude/airspeed combinations under which a safe autorotational landing is not probable. (A-03-18)

Require the manufacturer of the full authority digital electronic control system installed on helicopters equipped with Rolls-Royce Model 250 series IV engines to modify the system such that an erroneous or erratic in-range potentiometer throttle position angle signal will not cause an uncommanded increase or decrease in fuel flow, which could result in a drastic reduction in engine power. (A-03-19)

Prohibit the operators of single-engine helicopters equipped with Rolls-Royce Model 250 series IV engines from operating in those altitude/airspeed combinations under which a safe autorotational landing is not probable until it is shown that the operation of these engines provides an adequate margin of safety. (A-03-20)

Require, on an expedited basis, that the on-aircraft test procedure developed by Rolls-Royce to identify faulty potentiometers be performed, on a repetitive basis at a conservative interval, on all Bell 407, MD-600, and OH-58 helicopters to determine if the potentiometer contained in the hydromechanical unit (HMU) is working properly. HMUs with faulty potentiometers should be replaced. (A-03-21)

FMI: www.ntsb.gov/Recs/letters/2003/A03_18_21.pdf