Safety Publications/Articles


Learning from gliders

Consider this training for expanding pilot knowledge

Every student pilot should fly at least two sailplane flights before receiving a certificate for powered aircraft. Why? Because unpowered flight is the true teacher of both aerodynamics and weather. When a glider pilot encounters sink, the only option is to lower the nose to get through it quickly. By the same token, glider pilots can learn to soar mountain and ridge lift, yet must know when it's wise to return to base. In short, sailplane pilots are some of the most safety-conscious pilots flying.

While technology cannot change fundamental aerodynamics, it certainly has changed the way we fly. Magenta lines on moving maps may tell us where we are, but not necessarily what to avoid. Direct routing can take you over mountainous terrain--where waves and rotor turbulence can wreak havoc on your aircraft. Direct routing can also take you miles from suitable alternate airfields. Satellite navigation has simplified cross-country flying, but the degree of required flight planning has never changed.

Two airline accidents illustrate the need to expand our knowledge. The first involved a DC-10 in Chicago, where the number one engine (left pod) came off as the aircraft rotated on takeoff. The pilots saw they had lost power to the engine, but most likely they did not realize the engine had actually departed the aircraft. In response to the perceived engine failure, the captain rotated at the proper speed. Company procedures called for maintaining V2, the best engine failure speed. Sadly, the loss of the number-one engine pod severed hydraulic lines to the left wing's leading-edge devices, which retracted as the hydraulic fluid bled away, resulting in the stall speed being increased for that wing. As the captain increased the pitch, reducing the speed to V2, the left wing stalled. The altitude was too low to permit recovery. Company procedures were later changed to mandate that a speed of V2 or current speed be maintained, if the engine failure/separation occurred at a speed higher than V2.

As with any airline disaster, this flight was recreated in simulators in an attempt to understand what happened. One of the changes that came from this accident was adding 10 knots to V2 for the initial climb. In this case, the additional 10 knots may have made the difference between returning to the field or not.

Bear in mind, this DC-10 crew did exactly what they were trained to do. Unfortunately, their aircraft didn't respond accordingly. This is where experience with sailplane flying comes into play. There are times when you must trade altitude for airspeed, even when there is little altitude to spare. This applies equally to all aircraft, and is a thought that must be considered at critical times.

The second mishap involved an Airbus in New York in which the vertical tail separated from the aircraft. The crew was flying precisely the magenta line of the instrument departure track when it encountered wake turbulence from the Boeing 747 in front of it. There has been much debate over the crew's rudder inputs, and I am not willing to go there. However, had the crew leveled the aircraft's wings and slid to the outside of the turn, the chances of suffering structural damage would have been minimized. Once again, the crew was following their established procedures, but there are times when pilots must override procedures in the interest of safety.

Both of these incidents highlight the need to constantly evaluate your options. The time to think about emergency procedures is before anything happens. If you fly over mountains, be watching for a place to land should the engine fail. If you are in a multiengine aircraft, make sure your driftdown capability will allow safe passage. If over water, plan a route where someone is likely to pick you up, should there be a need to ditch. When flying a direct route, constantly update your alternate fields in case you need to divert for weather or mechanical reasons. This is what professional pilots do, and it is a discipline that applies to everyone.

These mishaps emphasize the need for basic airmanship. The term captain's emergency authority must be ingrained in every pilot's head. The FAA allows the pilot in command to deviate from any procedure in the interest of safety on the basis of this emergency authority. Whether you are flying a Cessna 172 or Boeing 777, the PIC can always waive the rules. All the FAA asks is that you declare an emergency and file an incident report afterward. The consequences of declaring an emergency are far less than the consequences of mishap.

Realize that my intent is to learn from these mishaps, not to find fault with any airline crew. Knowledge makes us safer pilots. Don't get complacent, be prepared, and take a glider ride some day. It's an experience that you will never forget.

Mark W. Danielson is a retired Navy pilot who currently flies for FedEx. He has been a CFI for 26 years and has flown more than 11,000 hours.

By Mark W. Danielson

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