June 2002

By: MG John M. Curran

                Imagine for a moment that you are the pilot in command of the UH-60 Black Hawk in the following vignette:

                "The objective, a pocket of al-Qaida near the border of Pakistan, is less than 8 kilometers ahead. The mission is to insert troops near the objective via our flight of five Black Hawks. We're inbound on chalk three and should be landing in a few moments.

                 "At zero illumination it couldn't be better for masking our flight but it also couldn't be worse for getting the 'pucker-factor' way up. The landing zone (LZ) is supposed to be a craggy, dusty bit of low ground just below a ridgeline and out of sight of the objective.  All of our aircrews are wearing Type 1 and Type 2 Aviator Night Vision Imaging Systems (ANVIS). Except for the artillery flashes in the distance lighting up my Night Vision Goggles (NVGs) all I see are the ghostly silhouettes and exhaust plumes of the two aircraft ahead of mine. There's plenty of 'video noise' in my NVGs, much like you see on a TV that's lost its signal.  That makes it very difficult to pick out ground references but we're all used to that on dark nights like this.

                "It's time. We've begun our approach to the LZ.  We're in a staggered-right formation with our flight stacked down so that our trail aircraft will touch down first. That will lessen the chance that the lead aircraft will brownout the LZ and make it impossible for others to land behind him.

                "Chalk four has just announced a go-around due to brownout! This could be ugly. He should be passing high and to my right but I'm way too busy to watch out for him. I'm concentrating on my approach. My crew chief is calling the dust cloud. 'Dust cloud at the tail!  MY door!  YOUR DOOR!'  I feel our tailwheel hit the ground just as we're totally engulfed in a vicious dust cloud.

                "The ground was a few feet from my nose when I lost sight of it so I elect to continue. My main wheels hit the ground hard. I stand on the brakes and we grind to a halt. At that instant I see a flash of light from my right front that shuts down my goggles for a moment. It seems like chaos as our troops exit left and right and fall to the ground with their weapons extended in front of them. As the dust cloud begins to dissipate I see the underbelly of chalk two to my right. There's a flicker of fire from one of their engines. It looks like they've rolled over in a crevasse.  I sure hope they're okay."

                The episode you've just read is fiction, but adrenaline-pumping moments like these are familiar to anyone flying these types of missions. Requiring split-second decisions, formation dust landings under NVGs are some of the most hazardous missions our aircrews perform. It's critical that airspeeds and approach angles are closely monitored and that crew coordination is well exercised. Get slow too early and you'll quickly brownout and lose contact with most, if not all, of your references. Land with too much forward speed and you risk colliding with unseen obstacles or other aircraft.

                Interestingly enough, about 65 percent of our aircrews perform this tremendously difficult task with the oldest ANVIS in our inventory, the Types 1 and 2 (type categories of ANVIS are fully defined in the latest ASAM, GEN-02-ASAM-02, available at www-rucker.army.mil/ATB/NVD/NVDB.htm   ).

                Type 1 ANVIS are equipped with 15mm eyepieces and a single Interpupillary Distance Pivot and Adjustment Shelf (IPD PAS), or have incorporated either improved 25mm eyepieces or dual IPD PAS. Type 2 ANVIS incorporate both improvements in the 25mm eyepieces and a dual IPD PAS to give the wearer the ability to fully adjust the NVGs for best vision. 

                All Type 1 and 2 ANVIS use the earliest intensifier tubes and provide just 20/40 vision during high-light conditions while providing only 20/120 vision during low-light conditions. While this equipment is still "good" and heads above the earlier ground NVGs flown in the late 1970s and early 80s, it's far from the best equipment produced.

                Type 3 ANVIS, used by about 20 percent of our aircrews, are essentially Type 2 ANVIS with improved intensifier tubes.  They give the wearer 20/33 and 20/105 vision during high- and low-light conditions, respectively. Type 1 through 3 ANVIS fall under the classification of AN/AVS-6(V)1 and have a typical "halo," a bright haze around light sources, of about 1.5 mm.

                Type 4 ANVIS are the best currently fielded. They fall under the nomenclature of AN/AVS-6(V)1A, or are an earlier AN/AVS-6(V)1 that has been upgraded with the latest intensifier tubes. The 160th Special Operations Aviation Regiment (SOAR) and select other aviation units have been using the Type 4 ANVIS for years. 

                Type 4 ANVIS are nearly twice as good as Type 1 and 2 ANVIS with high- and low-light visual acuities of 20/28 and 20/70, respectively.  First delivered in the mid 90s, these NVGs use more of an amber colored phosphor screen instead of the dark green phosphor screens that so many of us are used to. In addition, more emphasis was put on halo reduction in the Type 4s, which resulted in halos of no greater than 1.25 mm.

                The Type 5 is the newest member of the ANVIS family and uses the nomenclature of AN/ AVS-6(V)3. The Type 5 will first be fielded to the 160th SOAR and other high-priority units, beginning the third quarter of fiscal year 2002.  I won't go into detail, but suffice it to say that the technological improvements in Type 5 ANVIS are above that of Type 4. Units fielded with Type 5 ANVIS will have improved Military Operations in Urban Terrain (MOUT) capabilities. This is primarily due to the Type 5's ability to maintain crisp, clear images during overly high ambient light that would otherwise shut down other NVGs or provide only washed-out images.

                As the first units are fielded Type 5 ANVIS, the rest of our aviators will then benefit from a cascade plan that sends Type 4 ANVIS to the next-highest-priority units. As that plan progresses, more and more aviators will see tremendous gains in their ability to function at night. They'll enjoy higher resolutions, less halo and less video noise during low-light conditions. The cascade plan will continue until all the newer ANVIS are fielded and the older Type 1 and 2 ANVIS are purged from the inventory.

                Another bright spot in the area of Night Vision Device (NVD) improvement is with the improvements in the AN/AVS-7, Heads-Up-Display (HUD) and the fielding of the Advanced AN/AVS-7 Heads-Up-Display (AHUD). AHUD incorporates, among other improvements, an upgraded computer processor that gives aviators "real-time" information as to their flight profiles.  The fielding of AHUD was completed during the third quarter of FY 2001, and is installed in all CH-47 aircraft and approximately half of the UH-60 fleet.  The remainder of the UH-60 fleet received a software upgrade to its basic HUD that dramatically improved its speed (there is a plan in place to equip all UH-60s with an AHUD or better system in the near future).

                Commanders need to take advantage of the advances in HUD. Incorporating more of HUD in their unit ATP and having their crews use it during missions will enhance performance and reduce risk.

                Consider again our fictional but realistic troop-insertion mission. Perhaps our crews could have benefited from the use of Type 4 ANVIS and/or HUD. Though not the only considerations for a dust approach, better references for gauging aircraft speeds, angles of approach and rates of descent could certainly aid in successfully landing an aircraft before it is enveloped in brownout conditions. Perhaps the crew of chalk two might have been able to adjust their flight profile to avoid that disastrous crevasse if they had a clearer view of their landing point. 

                Although we are always attempting to mitigate risks associated with "taking care of business," our missions are routinely fraught with danger. NVG flights are intrinsically riskier than other modes of flight, but it's good to know that we are delivering better NVD equipment to our aircrews to more safely take the fight wherever it calls us. 

                That's what I call taking back the night!

 MG John M. Curran is the commander of the U.S. Army Aviation Center and chief of the aviation branch.