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Aviation Learning Center Document Silent Emergency: Pneumatic System Failure - P-8740-52
Author: Federal Aviation Administration Date: unknown
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Tips for Survival
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Know Your Airplane

Every pilot should know the instrument power sources for each airplane flown, and particularly know the consequences of loss of any source of power, air or electrical, or loss of any instrument, and be prepared to cope with the loss.

Know Yourself

Airplanes can be flown safely with loss of one or more gyroscopic instruments. Every instrument rated pilot demonstrated the ability to do so prior to receiving the rating. The problem is that many never practice the skill and only a few have ever practiced in turbulence, as it seems an unlikely need in routine operations.

Professional pilots who are required to take semiannual simulator training practice a lifetime of emergencies each training session although they rarely encounter emergencies in daily operations. Most general aviation pilots remain "current" by flying in the system and may rarely face or practice emergency situations. For most pilots, continued flight in IFR conditions with failed gyro heading and attitude instruments is a high work load situation that could lead to a fatality.

If You Are Not Instrument Rated

If you are not instrument rated and inadvertently encounter instrument weather, the 180 degree turn is usually the best course of action. If your pneumatic driven gyro instruments fail, it is still possible to make a 180 degree turn by using the turn and bank (or turn coordinator), magnetic compass and clock. Likewise, a descent through clouds to VFR conditions can be made using the turn indicating instrument. These procedures may be tailored to each airplane type and model and should be demonstrated by and practiced with an instructor. It may be too late to learn them when faced with actual need. Avoid conditions that risk encountering instrument weather.

If You Are Instrument Rated

If you are instrument rated and gyro instruments fail or mislead, do not be afraid to ask for help. ATC personnel know where to find better weather and are able to give "no gyro" heading directions. The whole system - radar, weather reports, communication, and personnel - is instantly available to assist you.

Do not try to be a "hero" and continue on bravely as if loss of pneumatic power is no big deal. It can be a serious emergency unless you have maintained high proficiency in partial panel flying.

Also, cover the dead or lying instruments. Most partial panel practice is done with covered instruments, but in real cases the artificial horizon will be sagging and giving erroneous information that your instincts want to accept as correct. Autopilots that use these instruments as sensors must be turned off immediately. Note: Again, you need to know your aircraft systems thoroughly, so that you will know how a pneumatic system failure affects other equipment.

Finally, if your airplane has no back-up capability, be very cautious in the type of IFR you fly. Solid IFR from takeoff to touchdown can be very difficult on partial panel.

Back Up - Better Way

If your airplane does not have a back-up, or stand-by system, and if you use your airplane for IFR flight, consider a back-up or stand-by pneumatic system. Several manufacturers offer a variety of alternate systems that will supply vacuum or pressure if the engine driven pump fails. While the chances of pneumatic system - or pneumatic driven instrument - failure while in actual IFR conditions has been demonstrated to be small, those same statistics also demonstrate that the cost of a stand-by system is far less than the too often fatal results of not having a back-up.

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