Transcript Night Vision Goggles Technology

Civil Aviation Use of NVG
Presented by:
Transport Canada
Operational Standards
Division
June 30, 2005
OUTLINE
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NVG Basic Concepts
NVG Characteristics
Human Factors
NVG/Aircraft Integration
Operational Considerations for
Civil Certification
Why Use NVG?
• Human visual performance under night
illumination levels very poor - 20/200 (full
moon) or worse.
• NVG - Enhanced visual performance 20/30
– Better spatial awareness
– Improved situational awareness
NVG Flight
• NVGs do NOT turn night into day!
• Is NVG-aided flight considered to be
enhanced night flight?
• Or is it more appropriate to consider it
degraded day flight?
Basic Operating Concept
• NVG - Used to view the outside
world
• Unaided Eye - Used to view the
cockpit
Anatomy of NVG
Objective Filters
• Prevent certain wavelengths from entering image
intensifier
• Allows use of properly filtered lighting to
illuminate cockpit for viewing underneath goggles
– Class A: blocks below 625 nm (blue/green)
– Class B: blocks below 665 nm (blue/green/reduced red)
– Class C: incorporates notch filter to permit viewing of
specific wavelength
Spectral Response
CLASS A/B/C
Automatic Gain
Control
• Designed to maintain image brightness and protect
tube from excessive light levels.
– Automatic Brightness Control - Provides
consistent output brightness by control of
microchannel plate voltage.
– Bright Source Protection - Protects the image
intensifier tube by control of photocathode
voltage.
Automatic Gain Control
Gain is constant, and noise increases
as illumination decreases
NVG adjusts to ambient
conditions from overcast
starlight to dusk/dawn
100
Gain (%)
Constant brightness
region
0
0
X
Illumination (mlux)
Airborne Complex Light Scene
NVG Performance Metrics
• Tube Gain - Ratio of intensifier tube output
brightness (in foot-lamberts) compared to
illumination of the input (in foot-candles).
– Gen III typical value: 25,000-60,000 fl/fc or 2500-6000
fl/fl
• System Gain - Ratio of output brightness to
input brightness (both in foot-lamberts) for
the complete system.
– Gen III typical value: 2500-6000 fl/fl
Signal to Noise Ratio
• Measure of image intensifier performance
• Defined as:
Signal (electrons produced by ambient light)
Noise (stray electrons)
Stronger signal produced by:
– More ambient light
– More sensitive photocathode
• SNR highly dependent on ambient light levels
Generation III - Improvements
• Gen III I2 tubes (1995)
• Photocathode sensitivity:
– SNR of 16
– 1000 A/l
• MCP channel diameter:
– 11 microns
• Tube gain: 25,000 fl/fc
• System gain: 2500 fl/fl
• Resolution: 36 lp/mm
• Gen III I2 tubes (2000)
• Photocathode sensitivity:
– SNR of 25
– 1,800 A/l
• MCP channel diameter:
– 6 microns
• Tube gain: 60,000 fl/fc
• System gain: 6000 fl/fl
• Resolution: 64 lp/mm
Spectral Response - Gen II vs. Gen III
Gen III
Gen II
NVG Low Light Capability Comparison
Generation I, II and III Comparison
NVG HUD
• Display flight and navigation information
• Eliminates need to look under the goggles
for aircraft system and flight information
• Increased safety
• Enhanced situational awareness
NVG HUD Image
Human Factors
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Visual Performance
Fatigue
Spatial Disorientation
Complacency
Visual Performance
• NVG FOV is 40 degrees
• NVG partially obstruct view of cockpit
• Visual Acuity is generally 20/30 at best
– Decreases in low light
– Decreases as contrast in scene decreases
• Monochrome image
Vision Physiology
• Day vision – Photopic (Cones)
• Night vision – Scotopic (Rods)
• NVG Image – mesopic (mixture)
– The NVG image is fairly bright, transition to
lower light levels takes time.
– Flight crews are not “dark adapted” while using
NVGs
Spatial Disorientation
• Visual Performance factors result in
increased susceptibility to visual illusions
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Black hole
Terrain Masking
Resolving object size/ Altitude estimation
Judging Closure rates with terrain/ aircraft
• Scanning techniques can result in
disorientation
Environmental Issues
• Summer
– Backlit Terrain (Terrain masking)
– Dust-ball (Loss of drift cues close to ground)
– Falling Rain (IIMC)
• Winter
– Snow covered ground (whiteout)
– Snowball (Loss of drift cues close to ground)
– Falling snow (IIMC)
Environmental Issues
Cultural Lighting
• Bright light in FOV – NVG Gain decreases
– Could make obstacles invisible
– Halos mask obstacles
– Difficulty picking obstacle lights out of
background
Environmental Issues
Remote Areas
• NVG sees reflected energy – don’t work under all
conditions
• NVG operating at maximum gain - scintillation
– Grainy image may mask precipitation (Inadvertent
IMC)
– Lack of resolution may make obstacles impossible to
see, make accurately judging closure rates impossible
Fatigue
• NVG Weight and CG – physical fatigue
• Visual performance factors – eye strain
• Increased Cognitive workload – mental
fatigue
• Decreased FOV and obstructed view –
physical fatigue
• Circadian Rhythms
Complacency
• Complacency can be caused by excessive
fatigue
• Pilot may overestimate NVG performance
– Decreased Visual Acuity – Don’t know what
you can’t see
• Flying with NVG has an almost video game
feel – this could lead to unconsciously
taking excessive risk
Human Factors - Solutions
• Pilot Training
– NVG Characteristics/Limitations
– Visual Illusions
– NVG Flying Skills – scanning, cross-check,
image interpretation – use of a terrain board
– Minimum instrument flying training;
requirement for pilots to be instrument rated
and current
• NVG Compatible Aircraft
NVIS Aircraft Integration
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Cockpit Lighting
Aircraft Exterior Lighting
Windshield/Window Transparency
Physical Constraints
Handling Qualities - AFCS
Failure Criticalities
• Severe-Major/Hazardous Failures
– Display of hazardously misleading imagery
– Inadvertent/Uncommanded illumination of NVG
incompatible Light
• Major Failures
– Complete Loss of NVG image
– Complete Loss of NVIS Lighting System
– TSO C164, and RTCA DO 275
NVG Compatible Lighting
General Requirements
• All sources of light in and on the aircraft must
not degrade the operator’s view of the outside
world through NVG.
• Interior light sources and displays must allow
the pilot to easily interpret flight, navigation
and system information.
• Exterior light sources must comply with
CARs/FARs.
Design/Certification Issues
• Prevent light leaks.
• Colour integrity/intensity to meet the
certification basis, including external lights.
• Daylight readability
• Minimize cabin/cockpit reflections by using
appropriate paint/curtains, etc.
• Continue to meet the aircraft certification
basis.
Design/Certification Issues
• Aircraft Configuration
• Maintain the qualification of all components
installed or modified for NVG purposes.
• STC Applicability
• Test Conditions - Facilities
• Test Equipment
Aircraft Certification Test Program
• Ground Test
– Assess windshields
– Assess Interior lighting
– Assess Displays
• Flight Test
– Assess Exterior lighting
– Confirm performance of cockpit
displays/lighting
Incompatible Cockpit Light
Poor Lighting Uniformity
Good Lighting Uniformity
Good Practice
Questions ?
Civil Approval of Aviator’s Night
Vision Imaging Systems
Programs utilizing Night Vision
Goggles
Background
• The development of ANVIS programs
utilizing NVGs is being incorporated into,
or considered by, organizations such as
HEMS, police, and provincial forestry
organizations.
OUTLINE
• The following slides provide
guidance for Canadian approval of
commercial ANVIS programs.
Definitions
• ANVIS – Aviators Night Vision Imaging
System
• NVG – Night Vision Goggles
• HEMS – Helicopter Emergency Medical
Services
Approval to conduct ANVIS operations
will be conducted in 2 parts:
• Aircraft Certification
Approval
• Operational Approval
Branch
Aircraft Certification Branch
Approval
• Approving the Supplement Type Certificate for
installation of NVG compatible lighting in
accordance with Airworthiness Notice AN BO53,
and Aircraft Certification Policy Airworthiness
Letter ACPL 29;
• Flight test for ANVIS compatibility;
• Development of the Rotorcraft Flight Manual
Supplement
• Only Night Vision Goggles conforming to TSO
C164 may be used
Operational Approval
• Evaluation of ANVIS ground and flight
training programs;
• Amendments to the COM including ANVIS
Standard Operating Procedures (SOPs)
• Monitoring of the training program;
• Observing training and operational flights
utilizing ANVIS
Additional Aircraft Equipment
• A searchlight, steerable from either pilot
seat, if night landings are to be conducted
anywhere other than a lit, night certified
aerodrome. This light need not be NVG
compatible;
• A Radar Altimeter;
• NVG compatible exterior lighting
Inspector Training
• It is recommended that Inspectors
responsible for companies that wish to
utilize this new technology receive training
in ANVIS evaluation techniques as well as
NVG operational training prior to assessing
an air operator’s ANVIS program.
Company Training
• Acceptable company training programs
should consist of both ground and flight
training programs.
Ground Training
• Ground training should consist of classroom
lectures, practical training and written
exams with records of initial and recurrent
training. The use of a terrain board model to
simulate light levels and contrast is highly
recommended. The following topics should
be covered:
Ground Training
• Theory of Operation;
• ANVIS Physiology and Human Factors;
• Terrain Interpretation and Environmental
Factors
• SOPs and Emergency Procedures
• Pre and post flight procedures
• Flight profiles and weather considerations
Flight Training
• The aim of ANVIS training should be to
“train to proficiency”. At a minimum, this
training should consist of 5 separate flights
of at least 1-hour duration to establish basic
NVG proficiency. Previous demonstrated
NVG experience; such as recent operational
military NVG experience may be
considered an acceptable alternative.
Flight Training
• Experience is considered current if it has
occurred within the previous 24 months.
During the last NVG training flight the
candidate’s proficiency should be assessed in a
manner similar to the pilot competency check
and the candidates training file should be
annotated accordingly. ANVIS flight training
should include the following items:
Flight Training
• Pre-flight fitting, testing, and adjustment
• Rehearsal of company ANVIS SOPs
• Line / route / mission indoctrination as
appropriate
• Enroute procedures
• Aircraft normal procedures including scanning
techniques and cockpit drills while using
NVGs;
Flight Training (cont’d)
• Aircraft emergency procedures and NVG
failure procedures
• Post flight removal, safe storage,and
maintenance considerations.
Flight Crew Requirements
• Safe and successful ANVIS flying requires
a high degree of instrument scanning
proficiency.
• Pilots conducting ANVIS operations must
hold a current Instrument Rating
Currency
• ANVIS flying is recognised as a skill that
degrades with time and lack of currency. Company
training programs must indicate minimum
currency requirements to conduct ANVIS
operations. The accepted interval to retain NVG
currency is 90 days. After that time, a pilot may
regain currency by conducting a training flight
with a qualified NVG pilot prior to conducting
passenger-carrying operations.
Flight Duty Time Limits
• Conducting ANVIS operations, and the
wearing of NVGs increases fatigue due to
increased pilot workload and by the weight
of the appliance itself. Flight and duty times
should be reduced for pilots conducting
NVG operations.
• The current recommended maximum for
ANVIS operations is 5 hours per night.
Company Operations Manual
(COM) Amendments
• COMs should be amended to contain, at a
minimum, the following information:
COM (Cont’d)
• Comprehensive SOPs for the conduct of
ANVIS operations including normal and
emergency procedures;
• Pilot NVG currency requirements
• Proficiency check requirements;
• Pilot training requirements;
• Company training pilot requirements;
COM (Cont’d)
• Crewmember training requirements and use
of NVGs;
• Recordkeeping requirements;
• Minimum safe altitudes;
• Weather considerations.
Current NVG Use
• The Alberta Shock Trauma Air Rescue
Society (STARS) is the first EMS operator
in Canada to incorporate an ANVIS
program into their operations.
• They service areas around the cities of
Calgary and Edmonton and some
communities in British Columbia
Type of Operation
• STARS uses their NVG program to reach
communities in mountainous areas that
would otherwise not be accessible due to
the nighttime lateral obstacle clearance
restrictions of Canadian regulations
(CARs).
STARS
• This is the first authority that has been granted to a
Canadian operator providing alleviation from
certain Regulations while using an ANVIS program,
in this case, the MOCA for night routes with respect
to lateral obstacle clearance limits.
• Restrictions on the authority include; T/C approval
of the ground and flight training program, presurveyed routes based on the use of TSO- C129
GPS units, increase in visibility on mountainous
routes to 5 miles, minimum altitude enroute will be
1000 AGL.
NVG Reference Material
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RTCA DO – 268 - CONOPS
RTCA DO – 275 - MOPS
RTCA DO – 295 – Training Guidelines
HBAT 02/04 - FAA Guidance
TSO C164 – Issued 30 September, 2004
FAA AC 27-1B/29-2C, MG-16
NVG Compatible Lighting Design Requirements
– MIL-STD-3009
Summary of Key Safety Elements:
• Thorough training of flight crews in both the strengths and
weakness inherent in the system.
• RADAR Altimeter.
• Aircraft lighting fully NVG compatible.
• Only TSO’d appliances used.
• 2 pilot multi engine environment with the capability to go
IFR if required.
• 1000 foot minimum ceiling and 3 mile minimum visibility
required for commercial night VFR (NVFR) ops.
• 5 mile visibility required for NVFR flight in mountainous
areas
Questions ?
Mike Laughlin
Program Manager
Rotorcraft & Aerial Work
Commercial & Business Aviation
Transport Canada
613) 990-1093 Telephone / Télélephone
(613) 954-1602 Fax / Télécopier
(613) 297-9017 Cell / Cellulaire
[email protected]