GAMECHANGER FAR 91.176

Landing without natural vision

FAA's new authorization permits touchdowns for aircraft using approved EFVS.


Training requirements for EFVS

Mark Humphreys, one of FAA's first pilots in the development and testing of EFVS, also led the agency's creation of evaluation and training of the new technology.

This regulation also establishes training requirements for persons conducting EFVS operations (§ 61.31), including new recent flight experience and proficiency requirements (§ 61.57).

This training however is broken into 2 parts to go along with the 2 types of EFVS operations. For the use of EFVS down to a 100 ft visual transition point, the operation in use today, the FAA has formalized training requirements and established formal currency and proficiency standards.

For the new EFVS landing rule, ground and flight training requirements have been established in addition to recent flight experience and proficiency requirements. The specific regulations are found in proposed FAR 61.31(I)(7), 61.31(I)(1), and (I)(3).

Better EFVS tech is developing

Terry King, FAA HQ leader in the development of enhanced vision regulations, is a pilot and human factors specialist. She coordinated the agency's bureaucracy to put into place the historic new operational rules and certification regulations for EFVS for all aircraft types and approvals.

For the ultimate use of EFVS in operation, new sensor tech will be added. Today's baseline infrared sensor configuration is essential to any advanced landing system becasue IR EFVS provides a high quality image, operates at night, and provides the critical "micro texture" of the surface needed for landing. The limits of the current systems have been pushed to garner new performance improvements.

Recent testing by a NASA/ Honeywell/Gulfstream in fog ranging from 1200 to as low as 800 ft RVR yielded an amazing success rate. But from a practical point of view, the new FAA rule is designed for an uncontested operation in very low visibility, and that will require new tech like millimeter wave sensors. These devices, like the cell phone in your pocket, don't get fuzzy in zero visibility.

Early tests by companies like Sierra Nevada Corp (SNC), which now have prototype 94 GHz 3D imaging radar sensors flying, show impressive images and performance. SNC is a world leader well known for development of commercial spacecraft ventures and cutting edge defense programs and is an early commercial entrant with the new sensor technology.

SNC's 2 primary innovative EFVS products operating in degraded visual environments today include Helicopter Autonomous Landing System (HALS) and Radar Enhanced Vision System, which is used for fixed winged aircraft.

Imaging radar technology has the virtues of coasting through fog and clouds like traditional radar, but because of the short wavelength, can also produce an image of the runway at far off distances of nearly 1 mile.

SNC has also blended imaging radar and SVS technology together to produce an EFVS that eliminates the question, "Where is the runway?" Early prototypes of the SNC technology are flying in helicopters and fixed-wing aircraft, and have piqued the interest of most all in commercial aviation.

The integration of the high resolution imagery from infrared and imaging radar sensors is expected to be a critical innovation of the coming race for all weather supremacy. This type of technology will provide the brute force probing of heavy fog and clouds, IR imagery will render high definition detail and the ability to detect approach lights in fog.

The word we will see often in the future from these systems is fusion, and the result will be a seamless continuous picture of them together to landing.

But that's not the entire story. Other equipment is coming including advanced Primary Flight Displays (PFD) designed with Combined Vision. CVS PFD flight instruments that include EFVS to monitor the approach are considered by many the next step in advanced flightdeck displays.

Functionally CVS provides a logical place to view EFVS for both pilots, but is also an answer to the copilot monitor requirement for advanced EFVS operations in the new regulations. CVS technology will also be a key feature in the integration of vision and terrain data and flight guidance.

LOAs now and more to come

Supersonic designs for aircraft now will have the option of advanced flightdeck designs that use EFVS technology.

In order to manage and regulate EFVS operations for landing, the FAA has decided to use LOAs or Letters of Authorization.

At first you may want to face in the direction of FAA headquarters and scream at the top of your lungs,"Why another LOA?" But of all the paper the FAA can find to feed you, they may have some logic on this one.

The agency is looking to put in one place the operational approval and confirmation of training, among other things. The authorization process also allows the agency to be more flexible. As new EFVS technology develops, it provides a means for the FAA to tailor an authorization to fit an operator's particular EFVS capabilities without having to do new rulemaking.

These new regulations may also help with the current European process, where some countries insist on an LOA. As time goes on, maybe this requirement could go away. But for all the various FAA depts that may be unsure of what to do, the LOA process provides a cookbook recipe for operator approval.

No need for front windows?

For decades a number of airframers have been designing high speed aircraft that addresses supersonic issues by reducing the size of the front window. I'm sure you remember the Concorde with its ability to drop its nose.

But it did so at a high weight penalty carrying all the mechanical machinery to deploy and retract the nose. Scaled Composites and Virgin Galactic have a Swiss cheese like approach to windows. They put them everywhere but in small dimensions.

Boeing even has a patent for a telescope through the flightdeck to the nose. But recent Gulfstream and NASA testing using high definition displays and sensors were tested to see if you could fly, land and taxi without a front window.

The answer to the NASA XVision Flight demonstration was no front window—no problem. Now with no need for seeing with natural vision, designers have another option, and one that includes the operational and cost benefit of continuous, unrestrained airport operations in essentially zero visibility.

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