-T / T / +T | Comment(s)

Monday, March 1, 2010

Flying Into the Abyss

Abyss: A deep or seemingly bottomless chasm; the regions of hell conceived as a bottomless pit; night flight over significant bodies of water.

By Dan Deutermann

Imagine for a moment that a single-piloted, passenger-carrying helicopter leaves on a VFR flight plan from its airport-based helipad, enroute to a remote island 20 miles offshore. The flight was intended to take off in the late afternoon, however the VIPs were delayed until after sunset. Weather is reported as overcast at 6K, 6 miles in haze, 28C, calm winds, and no significant weather is forecasted along the route. The VFR-rated pilot is current to fly at night, however all previous night flying has occurred overland primarily at the airport where he is based and, up until now, there has never been a need to go to the island at night. Yet the pilot is quite comfortable with the venture and is looking forward to logging some more night VMC time enroute to the familiar destination.

The pilot crosses the coastline and wisely elects to engage the flight director. As he levels off at 1,500 feet, he thinks to himself: “Man, it’s dark … just a couple of boat lights out here to look at—if that’s what those are. Okay, 15 minutes to go. Where is that full moon from last night?”

No moon and lower visibility from the moisture in the air on that warm, no-wind night are going to make that 20-mile trip offshore somewhat sporty.

Minutes later, while actively engaged in a “there I was” story for the captive audience in back, he fails to notice that the flight director has disengaged and that an insidious rate of descent has begun to develop. Taking a brief pause in his story, something suddenly sounds different to the pilot, and a sensation of pitching up begins to take hold. A quick glance outside reveals absolutely nothing but pitch black. A rapid scan to the instruments reveals a VSI showing 1,500 FPM in the “bad” direction along with a RadAlt blowing through 200 feet heading for 0. “It can’t be, I was on...” Splash!

This type of mishap is hardly unheard of, and not exclusive to the maritime realm. However, the night maritime environment doesn’t seem to get the attention it deserves. The conditions described above are technically VFR flight, but is it really VMC when you consider that there was no visible horizon? If there were any moon or stars you can bet they would be of no use as they were likely obscured by the overcast layer. The haze effect over water is only going to be amplified by a hot, calm-wind night and visibility could be far less than six miles, making the anticipated island lights at 20 miles not so visible. Additionally, the lack of wind significantly adds to the problem by glassy smooth water eliciting zero visual reference texture to perceive movement. Make no mistake about it, overwater flight with no visible horizon is an instrument meteorological condition (IMC) and with a little extra preflight analysis, you can anticipate it.

Now, one might jump to what a prudent pilot should do when faced with looking into total blackness over featureless terrain, but all too often pilots have a difficult time abandoning the plan they have already set forth to accomplish. Therefore a critical component to preventing fatal mishaps over lakes and oceans, which are caused by spatial disorientation, is to ensure aviators are imprinted early on with the appropriate mindset regarding this environment.

Once armed with this correct mindset, the decision-making process may perhaps begin with a more conservative stance and in turn may better serve to prevent flight into realms where that pilot’s abilities are likely to be exceeded. For this reason, I will refer to the night maritime world as the “Abyss”.

To those pilots who have baptized themselves with flight into the Abyss without the benefit of instrument skills, I am sure you appreciate the analogy and perhaps recall the eeriest of sensations from your experience (unless you are the type who really likes dark places).

Regardless of the reported cloud levels and visibilities, factors such as ambient illumination, potential marine layers, no winds (for those glass-like surfaces and increased moisture in the air on warm nights) and the lack of any reliable light sources (supertankers don’t count) must be accounted for prior to flight.

All these factors directly contribute to creating an environment that can only be characterized as a place without depth, a seemingly bottomless chasm. While not every night flight over water is going to present a black hole, if you point the aircraft offshore and that is what you see, then you need to make a decision as to whether you can really press on as if you were in VMC on a VFR plan. Even if you are heading to a single source of light on the horizon (like a small barrier island), realize that the visual illusions are plentiful when flying over water. If you weren’t contemplating using instruments from start to finish on this flight, stand by for lots of drama when spatial disorientation creeps into cockpit. Your inevitable attempt to rapidly establish an instrument scan will likely lead to a little more drama, and turning on the searchlight at lower altitudes to see the water can actually induce vertigo. Take the recent EC145 mishap off Captiva in Florida:

The pilot could not remember the exact sequence of the final 500-foot descent; however, at some point she remembered the medical crew commenting they “couldn’t see anything.” She responded, that the flight to Captiva is usually very dark over the water and there’s “never anything to see.” She remembered turning on the searchlight and shortly after, impacting the water. —NTSB: ERA09LA464 Accident, Aug. 17, 2009, North Captiva Island, Fla.

With so many helicopter jobs occurring over the water, one would hope that somewhere in a pilot’s training, instructors would set aside some time for discussing this realm. But my observations lead me to find pilots more focused on things like how to successfully ditch and what the required equipment might be to meet FAR requirements. Judging from discussions I’ve had with instructors—both military and civilian—they all acknowledge having been in places where it is “really dark,” searching desperately for some light source before they realized they had better get that instrument scan going and perhaps get an IFR pick up, if one was even available. Would you like to guess where most of their “really dark” experiences took place?

Student VFR pilots are told from day one to stay away from clouds and what to do if they inadvertently encounter IMC. It is treated like an emergency, because that’s exactly what it is for a VFR-only pilot. What about situations where there is no discernable horizon, or, at night, a visual surface light reference sufficient to safely control the helicopter? That last part would make it illegal to be VFR if you don’t have it (FAR 135.207), and unless your operation has been reviewed by the FAA administrator, flying IFR outside of controlled airspace is prohibited below 1,200 feet.

A pilot takes off to fly VFR with a solid 1,500-foot overcast and six miles in haze. Conditions will be VMC over the city all night long, no argument there, which is why the U.S. permits night VFR. So when the pilot points offshore towards a barrier island 20 miles away, the additional effects of no moon and the resultant lower visibility from the additional moisture in the air on that warm, no-wind night are going to make that 20-mile trip somewhat sporty unless there are some instrument skills on standby. Why? Because it is every bit the same as flying into clouds unexpectedly, and for some, the experience will lead to an all-too-tragic outcome.

When instructors are molding a student pilot’s ability to exercise sound “aeronautical decision-making,” certain environments are unfailingly emphasized as dangerous places to venture, i.e. thunderstorms. For helicopters, the opportunity to go inadvertent IMC is much easier since the ceiling and visibility requirements are less restrictive due to a helo’s unique maneuvering capabilities. If one is going to make a profession out of flying helicopters, just know that when it comes to inadvertent IMC, there are two types of pilots out there: those that have done it and those that will; especially if pilots are taught they need only analyze clouds and visibility for that “legal” rationale to commence aviating. Then you can bet it is only a matter of time until they find out the hard way that some places need more analysis than others, like the Abyss. For helicopter operations over water, U.S. regulations simply state that the helicopter must have an emergency flotation system for commercial operations and make no mention of IFR-related equipment. The gap between the definition of IMC and the actual conditions that require instrument skills is significant when you truly look at it, but can be mitigated by sound judgment through analyzing your environment and telling yourself: “if there is no horizon, change the plan.” You could even train your brain monthly by picking one of those no moon nights, maybe with lots of cloud cover, fly a coast line (ocean or big lake) and see the horizon painted with all those city lights (now you see it), then look to the water (now you don’t). Think: No Horizon = IMC, get on the gauges!

My personal philosophy after 18 years of maritime aviation is to treat going “feet wet” at night (and even on some days) as being in IMC. No exceptions! In the performance of my missions, if I need to descend below 500 feet over the water, it is through the use of an instrument scan to get me to a target. Perhaps I will use a flight director, but I will always have set limits, placed error traps, and have a well-briefed safety pilot to hold the line (sorry folks, I am one of those that is a real fan of dual-piloted instrument flight in helicopters).

Even when I am instructing in the Abyss on NVGs with a full moon out, I can be on the controls and easily distract copilots of all experience levels long enough to fly them uncomfortably close to the water or to trip their RadAlt warning horn. The trick is simply to know if I know their mindset has lead them to fly strictly using their Mark-1 eyeballs.

However, when it is so dark that there is no light for NVGs to amplify, then there will be no horizon coming through the tubes, and without a horizon for the eyes to interpret spatial orientation via mother Earth, you will no doubt have to rely on instruments in the very near future if you decide to press on with your flight plan. If one is not instrument qualified, or perhaps only a “little rusty,” the Abyss is not the place to fly as if VMC, however “legal” it may appear to be on the ground prior to pulling pitch.

Accident investigators say that unintended flight into IMC is one of the leading causal factors in fatal aircraft accidents. They point to specific human factors as contributors to the event. Like the fatal flaw mentioned earlier, so many pilots demonstrate the inability to abandon their current plan of action and replace it with one that has higher odds of survival. Many regions of the world prohibit night VFR and simply say you need an instrument ticket. Others give it special emphasis and have some minimum training requirements. For VFR helicopter operations in the U.S., a pilot must have “visual surface reference, or at night, visual light reference, sufficient to safely control the helicopter.” For those uninitiated to helicopter operations over water, know this: the opportunities for the last part of that statement to manifest itself abound, and you will be in IMC.

If you are contemplating bringing NVGs into your operation, take caution in attempting flights to places where you may have not gone before simply because you can now see more on the tubes. Even if you are not going to be operating over water, be aware that the Abyss has relatives, and going “green” is not going to always counter their similar hazards. If I had to look into my crystal ball, I would say that the incorporation of NVGs is not going to curtail many inadvertent IMC-related accidents in a certain industry that seems so desperate to get them. NVGs will certainly help in some cases, but the combination of existing regulations, inexperienced yet legally qualified pilots operating alone, and the self-imposed pressures driven by the pursuit of profits will continue to open an ample number of avenues to circumvent sound judgment. There is little doubt that NVGs enhance safety in our profession, but they also come with a new set of challenges and will best be discussed in a separate article.

Eventually, pilots may undertake instrument flight training and on day one the mystery of flying in a degraded visual environment unveils itself as the pilot begins to learn the complexities of this discipline. One becomes exposed to the procedures and techniques for safely operating aircraft with no outside references and overcoming the sensations of flight that create illusions. Illusions with complicated names like “somatogyral” or “somatogravic” with pilot-given names like “the leans” or “false climbs” will quickly overwhelm a visual-only reference pilot. Hopefully, as the pilot develops the ability to see the mental picture that flight instruments provide, he or she will also develop an appreciation for how fast these new skills may become degraded from disuse. But with knowledge comes power, and now that they are armed with these new abilities and certifications, their confidence is strengthened. Now inadvertent IMC doesn’t look so evil, and if it is encountered on a VFR flight, then all one must do then is start working in the ol’ instrument scan and make a radio call to ATC for some vectors, right?

What if it has been five months since you have flown at night or even practiced instruments? Couple that with flying offshore, heading GPS direct on the modes, well outside of radar coverage, and not even talking to ATC. Sprinkle on some IFR equipment being degraded or inoperative (which was acceptable in your mind at takeoff because no significant weather was forecasted and you are, after all, flying VFR). In the U.S., such an event is legal, sort of.

The mindset you begin a flight with is critical. The intent is to adequately establish this environment as one to venture into with great caution, no matter what level of experience or qualifications you may have. For the inexperienced, don’t just point to rules to justify your presence if you find yourself in degraded visual environments. Don’t treat your instrument skills as a backup plan and recognize the potential early by digging a little deeper during your flight planning so as to anticipate IMC. If you don’t, just remember, the Abyss and its relatives patiently await you.

The views expressed herein are those of the author and are not to be construed as official or reflecting the views of the commandant or the U.S. Coast Guard. LCDR Dan Deutermann is a Flight Safety Officer who currently flies the MH-65C Dolphin.

[X] Dismiss Ad
Live chat by BoldChat