Low-level maneuvering extracts its toll
Ah, the things we'll do when we're young and silly and low-time CFIs in a Cessna 172, egging each other on. As anyone acquainted with the topography of eastern Colorado and Wyoming can attest, you can fly for miles seeing nothing but scrub brush and broken fence rows. I admit it, we probably flew lower than we should have that bleak spring day, justifying our minimal altitude at the time with the conviction we could make a safe emergency landing should the need arise. And we did maintain at least 500 feet lateral separation from the cows we encountered.
Some cows are not so lucky. In another area of the country known for its great wide open, North Dakota, the pilot of a Cessna 170 made a low pass to check his cattle. Whether it was the pilot's poor depth perception or an unexpected growth spurt amongst the gentleman's cows, the 170 struck one of the herd with the right main landing gear, ripping it from the fuselage. Though the cow paid for its unusual stature with its life, the 170 suffered enough damage during the subsequent landing on a neighbor's strip to draw the NTSB's attention.
Safety strategies
- Learn aerobatic flight from a competent instructor
- Perform aerobatic maneuvers only after briefing the flight
- Initiate aerobatic maneuvers with enough altitude to safely complete the maneuver with room to spare, and comply with regulations
- Maintain minimum safe altitudes at all times
- Be aware of steeply rising terrain along your route of flight, and keep adequate separation from the terrain
- Know your airplane's performance and limitations by exploring these at a safe altitude and with an instructor
Common accident scenarios: low-level maneuvering
- Failure to maintain adequate terrain clearance
- Inadequate planning and decision making in beginning an aerobatic maneuver
- Inadequate altitude to success-fully complete an aerobatic maneuver
- Delayed recovery from an aerobatic maneuver
- Initiating a flight under the influence of a drug
At cruising altitudes, we maneuver freely. After a clearing turn or two, we fly in a cocoon of air that generally forgives us if we don't manage our altitude or airspeed perfectly. As we fly closer to the ground, that cocoon shrinks, and we see this reflected in our relative motion. However, as you know, it's that relative motion that gives us the sensations of speed and energy, thrilling many a pilot — and inspiring a degree of anxiousness in some.
The primary factor in keeping low-altitude flight safe is the pilot's attitude. Maneuvering close to the ground must be approached with caution and respect, whether during takeoff or landing, or in other operations.
Setting the scene
As a contributing factor, low-level maneuvering collects a number of accident scenarios in one bucket. In careful reading of investigation narratives, a large number — roughly 25 accidents out of 74 surveyed from 1998 to 2000 — appear to result from one pilot's wanting to show other pilots, friends, or family a dramatic portrait of his aviation prowess. Often the scene begins with the airborne equivalent of waving out the car window at a friend passing by on the street. Unfortunately, the pilot ends up communicating only a tragic combination of his divided attention and his proximity to the ground.
These accidents, on the surface, seem pretty easy to avoid. However, it only takes being tempted once to create a dangerous situation. Some personality types are more likely to assume this type of risk — the risk that grows the closer you are to the ground. For others, a sequence of events leads to out-of-character behavior. There's a feeling you get when you enter into unknown territory: a creeping, prickly sensation as your body readies itself for a survival response. Any time you feel this sensation, pause to think critically about what you are about to do. You can follow the letter of the law: If you heed the minimum altitude restrictions, and only go below 500 feet agl when approaching to land at an airport, you will keep yourself out of trouble. But trouble can happen at airports, too.
Aerobatics gone wrong
During a cross-country air race, airplanes are clocked at various checkpoints along the route. Typically, these checkpoints are airports, and in order for observers to verify the airplane's registration, the pilot flies low down the length of the runway, pulling sharply into a turn on course at the end. To facilitate these multiple low passes, race committees apply for waivers that allow flight for racing aircraft below 200 feet at each airport checkpoint. These low passes are planned, practiced maneuvers. They differ greatly from spur-of-the-moment, "I'm gonna fly low so my buddy can take a picture" low passes that eat airplanes at high speed.
Again, critical thought beforehand adds a blanket of safety to the maneuver. At towered airports, a low pass must be approved before it is executed. Even then, this doesn't mean the maneuver is without risk.
A pilot ferrying a new Pilatus PC–7 from Switzerland to the company's completion facility at Jefferson County Airport in Broomfield, Colorado, asked the tower for a "low go-around or flyby" as he was sequenced for landing. The tower cleared him for the option, and he was told to make a right traffic pattern following the flyby. This flyby, as it turns out, was common practice by company pilots to announce their arrival to the facility. However, what the pilot opted to do next was neither standard nor condoned by Pilatus. From witness testimony, the pilot lined up with Runway 29R, gear up and wings level. The pilot entered a "crisp" roll to the right, which took the PC–7 slightly over the adjacent taxiway. During a second roll to the right, however, control was "fairly sloppy." On recovery, the nose pitched down through the horizon, and the PC–7 continued to descend in a stalled condition, wings rocking back and forth, until impact near unlucky Taxiway A-13. Whatever possessed a competent pilot to perform an impromptu series of aileron rolls at less than 100 feet agl, we'll never know. But the lesson remains: Unrehearsed aerobatics contain levels of risk that are unpalatable. You tacitly accept this risk when you enter this unknown territory.
Crossing the line
The next category of low-level accident is an interesting subset, and one from which most pilots will immediately remove themselves: Those accidents that occur when the pilot is under the influence of any type of debilitating drug.
While the hazards of driving after consuming alcohol and controlled substances are well known and can be construed to be the same or greater when we fly, some pilots get trapped by over-the-counter medications as well. Judgment lapses, yes, but more important, reaction time slows if you have almost any cold medicine, or certain other medications, in your system. During cruise flight, a slow reaction time doesn't pose much threat. However, as we get closer to the ground, our margin for error tightens, and reaction time becomes as critical as it is on the interstate.
The remedy is simple: When you have symptoms that warrant use of medication, don't fly. Rest. It's better for everyone.
Ag ops
For pilots who like to fly low, there's an allure to agricultural operations. Gritty, tough Ag-Cats are loaded up with skin-eating chemicals, then depart from grass strips in the middle of nowhere, and drop a load precisely on the proper square of land. If the pilot times it just right, the drop ends at the last moment before the wires at the other end of the field are reached.
With this narrow envelope of safe operations comes additional risk. When most of your flying is done within 500 feet of the ground, your chances of hitting something rise, and this is borne out by the accident reports. If you choose this occupation, ensure that you're properly trained, fly reasonable equipment, and stay alert.
Even experienced pilots get bitten. Those who had listened to his pearls of wisdom over the years knew the pilot of an Air Tractor AT-502 as a great stick and grassroots aviation philosopher. He had over 4,800 total hours, with more than 1,000 logged in the make and model of aircraft, and he'd flown 110 of those hours in the 90 days preceding the accident. The Idaho potato crop he dusted that calm summer day was standard operating procedure. He marked the intended field with smoke bombs and turned to make the first pass to the west. On the second pass, a little more challenging because the pull-up would occur between two houses, he made a successful drop. Then, as he banked left to miss one of the buildings, he clipped some trees and crashed onto the Air Tractor's right wing and nose. While most pilots will never spray crops in their flying careers, this unfortunate situation illustrates how, as the margins close, the risk increases. The price of a miscalculation is high.
The business of flying low
Other operations that take place closer to the ground than most pilots typically fly also have increased risk exposure.
Wildlife spotting and power-line patrol fall into this category. With new cellular towers springing up like steel mushrooms after a good rain, there's simply more to hit down low. While a lighted tower is arguably easy to spot, supporting wires are not — and it's often those that are hit as a pilot steers to avoid intercepting the tower itself. The primary reference for the location of obstacles such as towers and power lines is sectional charts. To avoid these and other low-lying hazards, study current charts and keep in mind that new towers can be found in notams until their existence is translated onto a chart. While on a recent road trip to Virginia Beach, I found that Rand McNally also deserves an update from time to time, as my four-year-old atlas failed to show the new exit onto the state highway we wanted to take to the waterfront. More than six months old is too old for the cockpit, since the price can be quite a bit more than a moment's panic at missing an off-ramp on the freeway.
When the ground rises up
Mountain flying poses another challenge to low-flying pilots. The terrain below is so compelling it may entice the unwary to take a closer look. But again, even those who should know better can be talked into going too close and trapping themselves in a corner.
An airplane departed the Boulder, Colorado, airport on an autumn morning to take photos of the peaking aspen trees in the mountains to the west. The pilot in command was an airline transport pilot and well acquainted with flying in the local mountains. His passenger rented the airplane for the photo mission, and he was a private pilot as well. A mountain biker reported the wreckage near Lake Mahan, in the Arapahoe National Forest. The Cessna 182K was judged to be well within its performance envelope for the elevation, about 10,400 feet msl. The NTSB calculated that the 182's book climb rate at 10,000 feet was 720 feet per minute at 82 miles per hour.
As it so happens, this climb rate translates into about a 5.5-degree angle of climb. Terrain contours in the area of the crash show elevation gains of roughly 600 feet per mile, or 6.5 degrees — relatively shallow for a mountain ridge. Though the 182 is a capable airplane, there are a lot of mountains out there that beat it in the climbing game.
And then there's airplane vs. cow. It's clear that the pilot in this case lost too, even though his airplane was repairable (the cow wasn't). The moral of the story is, if you're using an airplane to check your cattle — or do anything else near the ground — it doesn't do anyone any good for you to get too close.
E-mail the author at [email protected].
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