Une autre étude sur les JVN aux US (désolé c'est en Anglais):
Night Vision GogglesBackground
The year 2008 was a dismal year for Helicopter Emergency Medical Service (HEMS). There were a total of 14 accidents that resulted in the death of 28 individuals, including 23 crewmembers and 5 patients. During this period there were also 6 serious injuries and 3 minor injuries sustained. Ten aircraft were destroyed with the remaining four sustaining substantial damage.
Two of these accidents appear to be anomalies in the HEMS operational world. The first is the accident on June 29, 2008 in Flagstaff, AZ (7 Fatalities, two destroyed aircraft). This is the first mid-air collision between a civil HEMS aircraft and any other aircraft. The second is the August 31, 2008 accident in Greensburg, IN (3 Fatalities, one aircraft destroyed), with the cause unknown at this time.
A factor that was common in the remaining 12 accidents, where there were 18 fatalities and 4 serious injuries was that all occurred at night with the pilot flying “Unaided” (without Night Vision Goggles, or NVGs).
Historically, night flying makes up about 38% of all HEMS flying. (Note 1) Logic would say that 38% of the accidents should also happen at night. This obviously is not the case for the year 2008.
What issues face the HEMS pilot when flying at night? True “night vision” using the rods in the eye is understood to be about 20/200 acuity (legally blind). This is not a serious deficiency when flying in an urban environment where surface lights are easily seen using the daytime receptors (cones) in the eye, but can become a significant problem when flying outside of a well lit environment, where typical hazards such as weather and terrain are difficult to see, as attested by the recent string of accidents. The use of NVGs raises the acuity level to 20/30, resulting in a marked increase in visual awareness.
In an effort to streamline NVG certification processes and provide for appropriate requirements for NVG usage in the cockpit, NEMSPA has been working with the FAA to resolve a number of regulatory based issues, including working with AFS 250 and Airworthiness on the following:
1) Removing the requirement for a second crewmember on NVG’s for any operation. (In process)
2) Clarifying training and checking requirements for NVG operations. In the past, these requirements have been unclear and vary from one local FAA office to another. (In process)
3) Address MEL (Minimum Equipment List) relief for NVIS components. There is currently very little guidance concerning these failures. NEMSPA has been working with the FAA to provide suggestions. (In process)
4) Streamline and simplify the certification of Night Vision Systems (NVIS) in aircraft. Currently the certification requirements have not kept up with advances in technology. (Little progress)
5) Encourage HEMS Operators to introduce Night Vision technologies to HEMS programs where appropriate. (Little progress)Recommendations
1- Remove the requirement for a second crewmember for landings at unimproved areas. This is an issue that was strongly supported by HEMS pilots in the NEMSPA sponsored survey concerning the use of NVG’s. Of the 365 pilots that responded to this question, only 11 disagreed or strongly disagreed, however 97% agreed that they would prefer to land “aided” without a second goggle-equipped crewmember, rather than landing “unaided”.
• The FAA has indicated in their 2009 Calendar, that this is an issue that will be addressed by September 30, 2009.
• NEMSPA is not recommending that the second crewmember not utilize NVGs. We would like to encourage the use of a second set of goggles by medical crewmembers, just not be restricted to “unaided” flight if the second set of goggles is unavailable, out for inspection, or the crewmember is not current or not on board. We have seen flights where the medical crew is dropped off and the pilot has to reposition for any number of reasons. When the pilot returns he would not be allowed to land the aircraft aided, due to the lack of a second crewmember on NVG’s.
• This issue is important to the HEMS industry. Programs may be willing to operate with two sets of goggles, knowing that they can still fly aided night when one set is out for inspection, or unavailable. With no legal requirement for the second set of NVGs, crewmembers will have the option to use monocular systems, which are less expensive and may be more user-friendly for medical crewmembers. It will also allow the pilot to land aided if there is not a crewmember on board. This will free up at least one set of goggles per base, and allow more programs to fly aided, without sacrificing safety, while reducing cost.
2- Clarify training and checking requirements for NVG operations.
• NEMSPA, in conjunction with the FAA has worked on this in the past. New guidance just released by the FAA has clarified these training and checking issues.
3- Streamline and simplify the certification of Night Vision Systems (NVIS) in aircraft.
• The current standards for certification of Night Vision Systems have not changed over the years. These standards were developed with previous generations of NVGs. Today’s NVGs are much more tolerant of outside lighting, and the certification standards should reflect this newer technology.
• NEMSPA will work with FAA Airworthiness to correct these issues.
4- Address MEL relief for NVIS components. There is currently no FAA guidance concerning NVIS component failures.
• Without standards, many aircraft are rendered non airworthy for NVG usage due to the failure of a particular portion of the NVIS equipment.
• Provide reasonable relief for the ability to fly with inoperative NVIS instruments and equipment. This should be a both an issue for maintenance and the pilot in command.
5- Encourage HEMS Operators to introduce night vision technologies to HEMS programs where appropriate.
• Operators can be encouraged to utilize NVG’s by increasing the minimum weather requirements for “Unaided” flight in low light areas, and by requiring greater terrain clearances when operating “Unaided” in these areas. Low light areas have been defined by the FAA in a previous AO21 Operations Specification.
• NEMSPA will work with the FAA to establish weather minimums that would strongly encourage operations outside of highly lighted areas to utilize NVG’s. Operations in these areas without the use of NVG’s would be at an altitude that should increase the margin of clearance, and should prevent controlled flight into terrain (CFIT) accidents if adhered to. The success of this initiative would rest on the enforcement of these standards by pilots, operators and the FAA.
NOTE: Although the use of NVG’s will enhance a pilot’s ability to see and avoid terrain and weather, there are some situations where the use of NVG’s may not be required, such as flight in highly lighted urban areas.
Note 1: Frazer, Air Med, Sept/Oct 1999