Download - Introduction of the mrh90 helicopter and top owl helmet for operational use by the royal australian navy pascoe

Headquarters Fleet Air Arm

MRH90 and TopOwl Navy Flight Trials

2010 AMMA/JHC Symposium

DR Glenn PascoeDR Glenn PascoeMBBS, FRACGP, DAvMedMBBS, FRACGP, DAvMed

Senior Medical Advisor Aviation Medicine Senior Medical Advisor Aviation Medicine –– NavyNavy

(Wing Commander, RAAFSR)(Wing Commander, RAAFSR)

AcknowledgmentLCDR Brad MacKayChief of Flight Test, AMAFTU



• TopOwl Helmet

•AMAFTU MRH90 FOCFT

Scope

MRH90• NHIndustries NH90

– Tactical Transport Helicopter (TTH) vs NATO Frigate Helicopter (NFH)

• Troop lift (embarked and land based)• Fly by wire, retractable U/C, • Glass and carbon fibre composites• MTOW > SK50 • Rear loading ramp • Manual fold blades and tail pylon


Aircraft Maintenance and Flight Trials Unit

• AMAFTU– develop aircraft modifications – maintenance and operational procedures – evaluate through flight test new and

modified configurations, procedures and equipment

– ADF’s centre of expertise for ship/helicopter First of Class Flight Trials (FOCFT),

– Ship/Helicopter dynamic interface assessments (Embarked Flight Trials)


FOCFT Test – What is it?


• Where the suitability of the ship / aircraft combination is assessed.

• Ship just as much as aircraft focused• Outputs not only limited to SHOL

– Maintenance & support facilities just as important

• Testing to define safe operational capability of ship / aircraft combination

TopOwl helmet mounted sight and display system

• Valid engineering trade-offs:– Good: See through capability, mass, CG, – Bad: Hyperstereopsis, lower performance



Binocular Cues for Depth perception

• Stereopsis - Angle of disparity

• Accommodation

• Convergence


Hyperstereopsis

• An illusion created when each eye views an image from sensors with an interpupillary distance greater than that of the human eyes


Hyperstereopsis - Effects

• Absolute distance perception– Objects appear closer

Right I² Tube

Target pointReal

distance of object

in the scene

I² tube optical axes

Left I² Tube

D

Normal IPD

DD

Perceived distance of object

in the scene

• Magnification of depth – objects appear stretched, out of shape


Hyperstereopsis - Effects

• Overlapping objects – If enough light to see object unaided, NVD

image will be over-layed on real world image

– May see three objects instead of one


Other TopOwl issues

• Colour vision– ADF allows for slightly colour

defective aircrew applicants (CP2)– Optics of the TopOwl visor results

in effectively looking through a “green blocker” when visor is down

– Will CP2 pilots be safe?– Is reflected wavelength band

narrow enough to not be a problem?

– What about LED lights?


Other TopOwl issues

TopOwl and deck operations

• Compensation for visual distortion is necessary on initial exposure– Adaptation to absolute distance perception

occurs fairly rapidly (5hrs initially then 10- 20mins for re-adaptation)

– Adaptation to magnification of depth (‘arm stretch’ or slope perception) not complete

• USMC concluded that use of Top Owl was unacceptable for deck operations – Different aircraft


Results of Testing – TopOwl

• AS350 trial: approximately 60hrs– Seated height appeared slightly lower than

normal– Different ‘apparent’ seated height unaided/aided:– Transition from aided to unaided flight

Unsatisfactory


Results of MRH90 Testing – TopOwl

• MRH90 trial: approximately 10hrs work-up and 10 hrs at sea– Adaptation was Satisfactory

• Misjudged distance mitigated– Normal wheeled a/c landing technique

• Establish ROD during quiescent period and land firmly

– Height estimation assisted by RADALT– ACMN wearing ANVIS-9 NVD– Unfamiliar objects appear closer


Results of MRH90 Testing – TopOwl

• Peripheral Cues– Enhancing feature– Allows peripheral scanning of a lit deck


FOCFT–Specifics of Flight Test

• Instrumentation• Deck Modelling

– deck motion limits with/without lashings

• Shore based testing– Initial TopOwl NVD flight testing in AS350– Low speed handling/ data collection– Simulated deck operations

• Sea Testing– Interface Testing– SHOL development


FOCFT – Specifics of Interface Testing

• Deck interface & facilities examples– Ranging & stowing aircraft– Folding / spreading– Maintenance & support facilities– Hanger suitability– Maintenance supervision– Aircrew briefing / mission planning– Weapons prep / loading aspects– Ship-based aviation facilities


Results of MRH90 FOCFT


• 18 days at sea• 19 Test Sorties• 252 Deck Landings (172 Day / 80 Night)• 36 Utility operations• Overall, Very Large Envelopes (SHOLs)• 4 Major deficiencies identified