Optical Conclusions

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The year was 1978, and I was a newly minted Helicopter Aircraft Commander (HAC) in the CH-46 Sea Knight with Marine Medium Helicopter Squadron 265 (HMM-265) out of Marine Corps Air Station Kaneohe Bay, Hawaii. We were preparing for our first deployment to the Western Pacific (West Pac) since the squadron’s reactivation in the summer of 1977. HMM-265 had been deactivated at the end of the Vietnam War, a mere 5 years before, and reactivated as part of Marine Aircraft Group-24, which was a composite group of 3 F-4 Phantom Squadrons and 3 Helicopter Squadrons, consisting of CH-46s, CH-53s, and a Detachment of UH-1N Hueys.

Leading up to our deployment, we were tasked with preparing for the various operational requirements we would encounter in our deployment to Southeast Asia and the Pacific Islands, to include day/night shipboard ops, day/night confined area landing ops, mountain area landings, and external lift operations.

The Hawaiian Islands provide some of the best overall aviation and particularly helicopter training opportunities in the world, with its jungle, mountain, maritime, and yes, even desert environments, depending on the island.

It is to this end, though, that one can get themselves into a heap of trouble on any given day if not cognizant of the dangers and pitfalls the landscape of these marvels of nature possesses.

One lovely, yet moonless evening, we were tasked with conducting night confined area and mountain area landings in forested clearings at the 2500 ft. level of one of the mountains in the northwestern part of Oahu, known as ‘The Kahukus’. We (myself and Capt. Phil Westcott, flying CH-46F Buno, 156424) would be guided into the LZ via the utilization of an approach light system, which was to be set up by the infantry of 1st Battalion, 3d Marines (Grunts) who were themselves conducting pre-deployment ops in preparation for the same ‘pump’ to which we were to be a part, called the GAIL (Glide Angle Indicator Light) device. GAIL was a ‘Vietnam Era’ system which, for its time, was fairly sophisticated and similar to the VASI/Fresnel Lens Systems used at most controlled airport runways and on aircraft-carrying vessels, only portable and battery-operated. The concept being the same and standard as any approach lighting system, where ‘yellow is high, green is good, and red is bad’. I was soon to discover, though, that all is not as it seems, particularly when the portable system is set up by well-meaning, hard-charging Marines, with limited or minimal experience and without the benefit of having the supervision of a Tactical Air Control Party member or assigned FAC (Forward Air Controller). Ironically, I was to do a tour of duty as their Battalion Air Officer, 2 years later and be the OIC of these very ‘hard chargers’ of which I describe. Talk about karma! Everything looked per usual, as I, at the controls in the right seat, started the approach with a right break over the CAL site at approximately 500 ft. agl, followed by a right extended downwind and right base to final after coming abeam the landing point (remember in multi-piloted helicopters, the command pilot sits in the right seat, not the left). The right, descending turn to a 300-foot, half-mile final accomplished, the glide slope beam from the GAIL should come into view halfway through the base turn, which it did that night, as advertised…all was warm and fuzzy and I had that ‘I got this’ feeling, not thinking, however, that eminent confusion and disaster were quite literally, right around the corner! Curious to any VASI/Fresnel system, is the fact that there is/can be an ‘in-between zone of confusion’, where the colors of the glide indicator lights ‘blend or meld’ into deceptive indications. Such was the case, THIS night, for THIS aviator… For if not set up precisely by the ground handlers, the GAIL can and was deceiving me into impending disaster, for below 200ft. agl the colors green (on glide slope) and red (below glide slope) tend to blend together to form, you guessed it, yellow, particularly on a humid, misty, evening in the mountains of Oahu. As my brain perceived this condition to indicate that I was too high on glide slope, I decreased collective and rate of descent, to compensate, until I got SOLID RED, at which time came the onset of confusion, vertigo, and ultimately the visage of a 75 ft. tall Australian Pine Tree that filled the windscreen as my co-pilot turned on the landing spotlight, 12 o’clock, dead ahead and unavoidable.

 

Bob Bleak
Aviation Consultant
Avenge, Inc.

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