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March 21, 2005

TINS*! There I was...

Military aviation is an unforgiving vocation -- it’s just as easy to get killed flying the friendly skies as it is flying the hostile ones. The following tale was originally published in Flightfax, Army Aviation’s safety ‘zine, in September 1997. I’ve added some short notes for clarification purposes, since we don’t have a whole slew of former AH-1F pilots dropping in to visit. Most of it will be in Flash Traffic/Extended Entry, ‘cuz John’ll get his trousers torqued if I blow the rest of the site out the bottom of your monitor.

The entire flight lasted less than ten minutes. For those of you who need instant gratification, we lived…

There I the front seat of a Cobra with a number-one hydraulic system failure, halfway down a 4800-foot runway, doing 50 knots about three inches above the pavement. Just the normal emergency procedure for this particular situation, with one pesky little difference -- we were flying sideways.

Gee -- glad you asked...

Gary and I were going out to fly some SP [Standardization Instructor Pilot] in the back seat vs. IE [Instrument Flight Examiner] in the front seat training (for me) and a few PARs [Precision Approach, Radar] (for him) -- a mutual beat-each-other-up to keep us honest. We’d flown together for about twenty years and our crew briefing usually consisted of, “We’re going out for a Standardization (or Instrument) Evaluation Ride. You know the maneuvers we’ll be doing -- got any questions?” “Nope. You?” “Nope. Okay -- let’s go do it!” This briefing, though, was a little different, because Gary was now the Honor Graduate of our Flight Facility’s second Aircrew Coordination Course [civil equivalent is called Cockpit Resource Management] -- only my extreme modesty prevents me from revealing that I had been his trainer. After a by-the-book crew briefing, he added, “Let’s prebrief two specific emergencies; first, an engine failure at altitude and second, a dual-system hydraulic failure.” After he detailed each pilot’s responsibilities for each emergency (again, by the book), he said, “If we do get a failure, I’ll fly because I’ve got that good ol’ three-to-one mechanical advantage in the back seat.” I said, “Sounds good -- and if you don’t ask for the emergency collective hydraulic pump when we’re a mile out on final, I’ll announce and then turn it on.” “Okay -- let’s go do it!”

To make a short story even shorter, we were five minutes into our flight when a noise like a blender full of gravel caused both of us to shrink a little further down into our armored seats. I’ve long-since forgotten the RPM of a cavitating hydraulic pump, but it’s a figure only Carl Sagan would comprehend. Two seconds later, the amok blender was joined by its friends, Messrs. Master Caution and #1 HYD PRESS lights. [Note: hydraulic fluid lubricates the pumps, and when a pump loses lubrication, it very shortly thereafter undergoes what the engineers laughingly describe as “catastrophic failure of structural integrity," i.e., it explodes. It’s also located right behind the pilot’s head. A number-one system hydraulic failure in an AH-1F means that your antitorque pedals are now about as movable as an I-beam. Which means that you have a problem keeping the pointy end in the direction you’re flying. Which is not a Good Thing.]

As briefed, Gary continued to fly while I read off the checklist. As briefed, he turned toward a suitable area for a “run-on landing at a speed of 50 KIAS or higher” -- which just happened to be home-station. [Note: there is a cheery blurb in the Emergency Procedures of the operator’s manual which states that, as the airspeed decreases to 40 knots, the aircraft becomes uncontrollable and control inputs are futile.] As briefed, I called Tower, declared an emergency and told the controller we’d be coming in for a run-on landing to the duty runway. Suddenly, the grinding noise stopped and Gary said that he had normal pedal control back. While we mulled over this new development, the pump began to cavitate intermittently for several seconds. Aha! We were losing fluid, but we hadn’t lost all our fluid; the pump was intermittently operational -- bear that in mind for later. A few seconds later, the pump resumed its annoying cavitation and (again, as briefed) I provided some additional pressure to the appropriate pedal whenever Gary called for an assist in maintaining heading. We then performed our by-the-book before-landing check -- as briefed.

Cut to final approach (and yes, I had announced, “We’re at one mile. Emergency collective hydraulic pump coming on,” and Gary had acknowledged -- as briefed). “We’ve got a slight crosswind, Bill -- help me out with some left pedal to straighten out the nose.” “Okay, left pedal coming in – geez, that’s stiff -- nose is straight down the centerline. Approach angle’s good, airspeed’s at sixty and before-landing check’s still valid. Hold everything until we hit and I think we’ll walk away from it, Gar.” We touched down at sixty knots in an impressive display of sparks, smoke and textbook Aircrew Coordination. As we slid through fifty knots, we came to the intersecting runway, which has a slight crown. It launched us upward a few inches and we became airborne again -- just as the hydraulic pump stopped cavitating!

Now go back to There I was and reread the rest of the paragraph. It’s okay -- I’ll wait...

When the pump grabbed the last few ounces of fluid, several things happened simultaneously: the nose snapped left ninety degrees, we rolled right about ten degrees, Gary uttered a scatalogical expletive, our airspeed decreased rapidly (due to the “barn door” effect), we began sinking back to the runway -- and the pump resumed its manic cavitation. Ooops -- we hadn’t briefed this...

I had a nanosecond visual of each of our three options for dying --
1. either the rotor blades would hit the runway, fling us vertical and five tons of metal and jet fuel would come down on top of us, or
2. the skid would hit and become a pivot, flipping the canopy into the pavement and we’d get abraded from the top of our helmets down to our shoulders, or
3. the stub wing would hit the runway, crush the fuselage and rupture the fuel cell, turning us into a large, open air barbecue.
-- not a one of ‘em appealed to me.

My Aviation Career Objective was now reduced to living through the next three seconds and appeared to be somewhat in jeopardy.

I then did something we *hadn’t* briefed; I planted both size-twelves on the right pedal and shoved -- just as Gary hollered, “Right pedal!” The nose s-l-o-w-l-y reoriented right, the right skid-heel grabbed the runway -- followed rapidly by the rest of the right skid -- and we wobbled down the runway, teetering on one skid for several amusing seconds until the left skid decided to get with the program, too. We ground to a halt right next to the crash/rescue folks, who gave us a standing ovation for not plowing into them.

We performed a normal shutdown, but it took me three eternities to get two feet unstuck from an area that Bell had designed to accommodate one; my legs deciding to lock in the straight-from-the-hips position didn’t help the situation. One of the asbestos-suiters came over and said that Ops had told them we’d probably “need this” and handed Gary a roll of Charmin. Glad somebody thought it was funny…

Eighteen months later (almost to the day), after regaling a relatively new Pilot-in-Command with the story, we were on short final to our weed patch and

Heh. “Twitchy Bill”…who told you, John?