Red-Tape Woes: NVG Patch Work

By Charlotte Adams | October 1, 2008
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Important tools for flight safety, NVGs’ broader application is impeded by varying and confusing FAA rules on their installation and use.

Although night-vision goggles (NVGs) are becoming commonplace in emergency medical services and law enforcement operations, and the FAA says it encourages their use, questions remain about what is and is not allowed in operations and modifications.

There is a lack of standardization in the language used in supplemental type certificate (STC) documentation, according to those seeking or charged with approving installations of the devices. There are discrepancies between the procedures and regulatory interpretations used among the FAA’s different Aircraft Certification Offices (ACOs), affecting installation companies, and different Flight Standards District Offices (FSDOs), affecting operators. The FAA, however, is becoming aware of these concerns and appears to be addressing some.


Despite almost 10 years of civilian experience with NVGs, the devices were not, as of August, explicitly covered in U.S. Federal Aviation Regulations (FARs). Instead, they are addressed by individual operators’ operations specifications (OpSpecs), which have the force of regulation, and a collection of FAA notices, orders and handbooks, as well as STCs, manuals and other documents.

This patchwork approach may reflect the bottom-up evolution of the FAA regulation. The FAA was, in a manner of speaking, dragged into the NVG arena by Rocky Mountain Helicopters, the former air ambulance company that had to sue the agency to get the ball rolling. In the intervening time, the FAA has issued about 55 NVG lighting STCs covering more than 40 models of helicopters from all major manufacturers, mostly for EMS or law enforcement rotorcraft.

"Part of the problem is they just didn’t know what box to put [NVGs] in," Jim Wisecup said of the FAA. He is a board member covering regulations and standards for the National EMS Pilots Assn (NEMSPA). The FAA regulates the devices as "appliances," although an appliance typically is connected to the avionics. "Goggles to me are as much an appliance as bifocals or sunglasses," he said.

Another problem is bureaucratic churn: once a person in the FAA is "educated" on NVG issues, that person moves up to an administrative position or moves out, he said.

On the operational side, a huge issue in the EMS sector is the policy of requiring, in single-pilot operations, two crewmembers to be on goggles while landing at unimproved sites to assist in obstacle identification. (Most EMS operations are single-pilot.) If another person besides the pilot isn’t trained and equipped with the devices, the pilot is supposed to flip up the goggles at 300 ft agl. A related issue is whether the second crewmember can be on monocular goggles. Monoculars are smaller, weigh less, and are less restrictive than binocular goggles for medical personnel who may be riding in the back seat. Although the term, "night-vision goggle," is understood to imply binocular goggles, some operators have been approved to have the second crewmember on monocular NVGs, said Ron Fergie, a NEMSPA board member.

The language about having two crewmembers on goggles is found in the Rotorcraft Flight Manual Supplement of some STCs, but not others, according to Wisecup. "Template" language for the Supplement is found in Advisory Circulars AC 27-1B and 29-2C. Once in the limitations section of a Supplement, the language is always considered regulatory, he said.

Wisecup traces the two-crewmember rule in AC 27-1B to RTCA’s DO-268, entitled "Concept of Operations — Night-Vision Imaging System for Civil Operators," which was published in 2001. Regarding "remote area" landings, DO-268 says, "consideration should be given to employing additional scan the opposite side or in back of the helicopter due to limited field of view...and field of regard." But when addressing single-pilot landing operations to an unimproved site, AC 27-1B says, "An additional crewmember shall be equipped with and use NVGs during landing to assist in obstacle identification and clearing." The word "should," according to the FARs, is permissive language, whereas "shall" is restrictive language, Wisecup explained. So the FAA essentially made the RTCA’s advice a requirement without going through a regulatory process or consultation with industry, he said. This change was not inserted into the AC until 2006, although the agency had been requiring it (with some, perhaps unintentional, exceptions) virtually the whole time, he said.

While few would dispute the value of having another pair of "aided" eyes in the cockpit, an absolute requirement to do so could pose difficulties in some circumstances. For example, a pilot with a second, NVG-equipped crewmember (such as a nurse) lands, "aided," at an unimproved landing zone and drops off a crew, which travels cross country to pick up a patient. But if the pilot then goes off to refuel and comes back to the landing zone with no one else aboard, the rules change. The pilot now can land unaided but is technically forbidden, below 300 agl, to wear the goggles. It is clear from a survey published by NEMSPA that some pilots are prepared to ignore the policy if they feel safety is threatened by it.

"Why can a pilot land to a site unaided and then is not allowed to land to the same site aided?" asked Ray Murphy, a former FAA principal operations inspector. Murphy questions the legality as well as the logic of the policy. "Medical crewmembers are passengers, and legally we cannot assign safety-of-flight duties to a passenger and then consider them crewmembers," he said. The FAA itself, in FAR Part 1, defines a "flight crewmember as a pilot, flight engineer or flight navigator assigned to duty in an aircraft during flight time," Murphy added, so that the agency’s Air Carrier Operations Branch (known by the organizational designation AFS-250) "is stretching the scope and intent of" the term. FAA proponents of the rule, on the other hand, point to Part 1’s parallel definition of a crewmember as "a person assigned to perform duty in an aircraft during flight."

Medical crewmembers can be a CRM (crew resource management) asset, Murphy said. The second crewmember can be "a valuable tool" on high recon for landing at an unimproved site. If medical personnel are "uncomfortable about the landing site, that pilot needs to listen to their concerns."

But to start requiring the second crewmember "to give safety-of-flight information to the pilot and, further, dictating what kind of equipment they use, is not allowed per FAR," he said.

Murphy argues that "if a pilot cannot land to a particular site with no assistance from a passenger or a supposed additional crewmember, then he is in the wrong place at the wrong time and should not attempt an approach and landing no matter what a passenger should say."

The FAA seems open to discussing this issue.

"We offered to work with industry and take a look at the new systems and evaluate them and make a determination about whether or not we could approve them for operation with a single individual," said Director of Flight Standards Jim Ballough.

In late August, NEMSPA arranged for three FAA officials to fly at night in a Bell Helicopter 407 in the Wasatch Mountains near Salt Lake City, Utah. The aim was to demonstrate the capability of new-generation, ANVIS-9-class goggles and make the case for rolling back the two-crewmember rule. While flying the FAA visitors up a canyon, Wisecup asked them to flip their goggles up, at which point their comfort level went down, he said.

"They definitely got past the field-of-view issue," he said, alluding to a limitation used by the FAA to justify the two-crewmember rule.

NEMSPA plans to follow-up with a letter to FAA aircraft certification officials. The association hopes that eventually they will indicate to the FAA field reps that the agency is willing to accept changes to the two-crewmember policy. Then the STC holders would have to go back to the FAA and ask for the changes to be approved. In response to a Rotor & Wing query, the agency said that a review of that policy, initiated after a formal request from NEMSPA, "is in progress."

Discrepancies in NVG policies on the operating side have prompted a desire for a "realistic set of guidelines to go by," Wisecup said. He said he would like to see "something very clear for inspectors in the field," so that what the FAA allows operators to do in Salt Lake City is the same as what they allow them to do in Atlanta.

The goal is to have the FAA and industry agree on a set of expectations on "how we’ll operate NVGs in the future," Wisecup said.

That sentiment is echoed on the installation side, although here too the FAA has been moving forward. REB Technologies President Richard Borkowski remarked that different interpretations of requirements between the respective ACOs in the past could sometimes make the cost of the same modification more expensive in one region than another. But all of the installation and modification vendors with whom R&W spoke expressed high praise for recent FAA efforts to rectify that.

As a result of complaints about FAA discrepancies, the FAA’s Rotorcraft Directorate has "started coming down" on companies, Borkowski said. "They went through every STC and every drawing we’ve ever done."

Night-vision STCs are different from others, Stubbs said, because the STC lighting kit changes with every aircraft. Even sister ships in the same hangar are "going to have different equipment that has to be filtered differently," with additional documentation covering different equipment. "That’s what the FAA is trying to get control of," he said. Stubbs would like to see a "guideline on what is expected of NVGs and what is expected of STC holders."

Meanwhile, the Fort Worth ACO has asked industry for some changes in STC paperwork, Stubbs said.

Most vendors already provide a "complete drawing package for each individual aircraft" as part of the STC, a common engineering practice. The Fort Worth ACO requests that all vendors document which equipment in a modification is supplied by the original aircraft or component manufacturer. "So you can look at this aircraft drawing now, and you see everything we modified, and on the last page, it’s got all the equipment that was already purchased," Stubbs said.

Another change per the ACO is a diagram at the back of the master drawing list, which makes it easier to see at a glance which modification drawings are related to which aircraft configurations.

Unauthorized changes to certified configurations are also a source of concern. Dan Hewitt, president of Aero Dynamix, for example, considers externally applied filters a big issue and very real concern for operators’ safety and airworthiness.

"It’s a cheap and easy fix to reduce infrared for nighttime use," he said, but "the biggest problem is you can’t see it in the daytime and that increases pilot workload during the day."

Plastic filters are being cut out with scissors and stuck on the front of instruments, Hewitt said. Daytime pilots "rip off the filter to read the instrument and then the aircraft is grounded because the modification has been removed."

The FAA is not considering any "best practices" guidelines for NVG lighting modifications. The agency said: "There is no plan to require a standardized way to modify a cockpit for night-vision imaging systems (NVIS) lighting. The FAA mandates minimum safety standards [set forth in FAR Parts 27 and 29] that a product must meet, but does not dictate to applicants how to design a product to meet those standards. We do however provide acceptable means of compliance, not the only means, in advisory material." The FAA goes on to describe some of the methods used to make lighting might-vision-compatible. These include: "applying filters to displays, instruments and individual lights; disabling of the basic rotorcraft interior lighting and illuminating instruments with floodlights or post lights; internally modifying avionics light sources to emit NVIS lighting; adding modified edge-lit panels that reduce the infrared signature; or an appropriate combination of these."

"Whichever method is used," the FAA stressed, "the certification requirements do not change." The agency "uses a standardized checklist to evaluate" each STC for compliance with the minimum safety standards, it explained. During an NVG lighting evaluation, the FAA verifies that the colors of lights are consistent across the cockpit, no glares have been created, the lighting does not bloom or degrade the effectiveness or acuity of the NVGs, and all instruments can be accurately read.

Night-Vision Cockpit Technology

There are three different methods of modifying the cockpit lighting systems for NVG compatibility: Post lights and floodlight lighting, installing a filter externally over the instruments and or the entire panel, and installing overlays and internally modified units. Each system will give the same result by reducing the infrared light to the point where it will not interfere with the operation of the NVGs. However, the quality of each type of modification is not the same.

When post lighting or bezels are added to the instrument panel, the post light protrudes from the panel and the bezel surrounds the instrument and illuminates the face. Wiring modifications are required and the post lights can create some visual blockage. Flood lighting is another solution, however, shadows and uneven lighting will cause readability problems unless the installation location is chosen carefully. Installing a special filter glass externally over the instruments panel and radios is another method. However, while this can work well for nighttime flying, daylight operations become a challenge as the filtered glass reflects the incoming daylight as well as distorting the placarded colors of the gauges.

According to Mike Guinn, repair station manager for Aero Dynamix, these are the less expensive solutions, however, they are not the best options for a properly lighted NVG cockpit. His company has completed more than 5,000 FAA approved modifications for both interior and external aircraft lighting systems and based on that experience believes that overlays and internal light modification provides the best quality lighting.

Guinn added that although NVG filtered lamps are larger than standard lamps and require some modification, no wiring changes are required. Subminiature NVG compatible filtered lamps are carefully fitted and installed in the instrument. Radio displays are modified by adding IR absorption/contrast enhancement filters optimized for the display type (LED, gas discharge, LCD or CRT). Control head backlit panels are replaced with NVG compatible panels. This modification procedure requires a functional test of the modified unit to verify airworthiness.

ASU Follow-Up

By Charlotte Adams

In the wake of its recent brush with the FAA, Aviation Specialties Unlimited has "fixed the problem, and our product now is better than it’s ever been," said company President Mike Atwood. The issue "had to do with configuration and conformity," he said, and some of the aircraft in question had been flying two or three years with no incidents.

Responding to queries from Rotor & Wing, the FAA said that the agency had "determined that ASU had modified a specific model of aircraft to operate with a Night Vision Imaging System (NVIS) using a supplemental type certificate (STC) issued for a different model of aircraft." For night-vision systems, STCs have to be not only make- and model-specific, but also serial-number specific, given the variations in cockpit instrument configurations, the agency said.

"The FAA determined that the modified aircraft were not unsafe, but that the incorrectly completed paperwork had to be corrected." It added that one of its employees, who had "not followed FAA policy and issued field approvals for some of these modified aircraft," was disciplined for doing so. The agency said it "is in the process now of reviewing the paperwork of all ASU-modified aircraft and issuing one-time STCs to those that were improperly returned to service."

The FAA said it has "grounded no [ASU-modified] aircraft," and "in fact, in determining how to fix the paperwork, wanted to move carefully so as not to force self-grounding by operators." The agency told R&W that when it "looked at some 10 modified aircraft early into this issue, it found that the modifications had been done incorrectly on two aircraft — one was a public aircraft and the other was no longer in service."

As far as preventive measures, FAA said, "an independent team examined this issue... and has made a number of recommendations," such as "better communications between Flight Standards and Aircraft Certification when issuing STCs [and] better coordination within Aircraft Certification." But the agency maintains "existing policies and procedures are adequate. We believe the disciplinary action taken against the FAA employee for failing to follow policy is sufficient incentive to keep this from recurring."

REBTECH said it has remodified one California Highway Patrol (CHP) Eurocopter AStar B3 originally handled by ASU. REBTECH was going to remodify two other CHP B3s, but the agency "lost their budget" for the work, Jeff Stubbs, REBTECH’s senior vice president of operations, said.

The Texas Department of Public Safety (DPS) operates eight ASU-modified AStars — a combination of BAs and B2s. The FAA inspected one of these aircraft as a representative sample, according to Assistant Chief Pilot Bill Nabors. The inspector initially raised a filtering issue, but that was resolved, Nabors said. FAA has told DPS that "nothing is unsafe about [the installation] and let us go ahead and keep operating." The aircraft "weren’t grounded for a minute," he added. "ASU will make the paperwork right, get the plans approved and then give us the corrected STCs."

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