Cockpit voice recorders for instructional flights
A lot goes on in the cockpit during a typical dual training flight. No one has the ability to remember every item that was learned in the cockpit. A typical student will forget 10 percent of the lessons learned before the end of the flight. Another 10 percent will be lost before the end of the day. Only 50 percent will be remembered after one week. It is human nature to forget. Unless the experiences are committed to long-term memory through repetition, experiences will be short-lived.
The modern equivalent of the tape recorder is the all-electronic digital voice recorder. Digital recorders smaller than the size of a cigarette lighter can be bought for less than $100. They can record several hours of audio, which can then be replayed or downloaded onto a computer. The CFI and the student can both take a copy home. The files can be shared through e-mail or over a Web site.
Their compact size makes these recorders ideal for cockpit use. All that is required is an intercom input. While it is possible to create a wiring arrangement to plug it directly into the intercom system, there is a simpler method. A tiny condenser microphone attached to the inside ear cup of the headset using a small piece of Scotch tape will work just fine without any elaborate wiring. These microphones are available from any electronic supply store for a few dollars. This arrangement does not affect the operation of the headset in any way.
Critics may question if there really is a need to introduce yet another electronic device in the already crowded cockpit environment. Every piece of equipment must be weighed with respect to the potential benefit it brings and the level of distraction it causes. Compared to other equipment in the cockpit, the recorder doesn't require attention from the pilot. It is turned on before engine start and turned off after shutdown.
This technique does demand the investment of time from both the instructor and the student. The instructor has to take the time at the end of the lesson to transfer the audio into a computer and send it to the student. The student has to take time to listen to the audio. Experience has shown that the students who diligently listen to the audio have a higher retention rate, shaving several hours off their flight training.
Not all digital recorders have a computer interface. A USB connection that allows fast downloading to a computer is an important feature. Recording capacity also varies greatly from one unit to the next. There are some units that can store as long as 16 hours of continuous recording. Another important feature is the voice activated recording (VOR) capability. This allows the recorder to skip over silent periods. For example, a one-hour flight may only contain 40 minutes of actual conversation or radio chatter. Some units also have a threshold setting for the voice activation. This is a handy feature because it can be set to the precise level to eliminate the background cockpit noise, just like the squelch control in the intercom system.
The recording quality is comparable to what comes out of the intercom. Any higher fidelity in the recorder will simply be wasted effort. Once the audio is downloaded into a computer, it can be transferred into any format using a number of shareware or commercial software.
This technique works so well that it is surprising why more people don't use it. It is a small investment with high returns. It can be used even under IFR, as voice recorders are explicitly exempt from FAR 91.21. If the student is conscientious about listening to the audio after each flight, the training time can be reduced by as much as 10 to 20 percent. It also helps to preserve the memory and sentimental value of those early training flights in much more vivid detail than a logbook.
Andrew Sarangan is a CFII based in Dayton, Ohio. He is a professor of engineering at the University of Dayton, and he teaches for the aviation technology program at Sinclair Community College.
