Friday, August 17, 2007

Eggs in a Basket

It's being reported that there is a defect in some Garmin G1000 Attitude Heading and Reference Systems manufactured after May 1 of this year. Apparently the AHRS can fail, leaving the pilot(s) to rely on the standby attitude instruments and the magnetic compass. Apparently this problem is serious enough that it has interrupted the production of aircraft at Columbia and several hundred employees there have been laid off.

When I train pilots in a G1000 aircraft, they often like to do things the easy way: Program in a flight plan, engage the autopilot, fly a coupled approach, and let the technology do the work. And why not? Some pilots complain when I require them to tune the frequencies and monitor the VORs that define an airway because it's a lot of work. "Is all this really necessary?" they often ask. The answer depend on how thorough you want to be and how much you want to trust your life to the technology behind those pretty colors on the screen.

For their part, Garmin hasn't made the use of VORs in the G1000 a simple proposition. Sure, you can learn all the button pushes and knob twists that are required, but the design is far from being user friendly or even thoughtful. The practical side of this is that I teach pilots to use what they have in an effective and safe manner. Use what you have, even if it frustrates you or if you have to hold your nose while doing it.

Some pilots I talk to think they need to know how to use each and every feature of the G1000 system. My feeling is that you could spend many hours of training and still not learn all the bells and whistles. In fact, and this is important, I think learning all of the features is pointless and is a distraction for the primary job of flying the airplane.

I do like to teach pilots to fly the plane with an AHRS failure, though this is controversial in some quarters. Part of the controversy stems from the fact that the instructor must pull two circuit breakers to simulate the AHRS failure. Some instructors argue that this should never be done as part of training, claiming that a circuit breaker is not a switch and that repeatedly doing this could cause that very circuit breaker to fail. Geez, I've been pulling CBs to simulate landing gear failures and the loss of engine instruments in twin aircraft for years. I've yet to see this have any adverse effect. I think the bigger disservice is to not prepare a pilot for something that could happen in flight, especially for pilots who insist on doing things "the easy way."

The G1000 systems have not been out that long, but their modular design should (theoretically) make it easy to replace a component if it fails. Still, we don't yet have a lot of reliability data on these systems. I will say that while the replacement of a G1000 module may be simple, it isn't cheap. The owner of a late model Cessna I fly had one of his G1000 GPS units fail under warranty. Though he didn't have to pay a cent, the replacement cost of one GPS receiver was equal to the cost of a late model used car.

Of course you don't have to use the VOR receivers in a G1000 plane, but it's a skill that you should practice. Of course you don't have to hand fly an aircraft for hours on end, but you need to be proficient in hand flying in case the autopilot fails on a dark, stormy night. Of course you don't need to practice a G1000 AHRS failure, but remember there's a definite tension between simplicity and safety, between cost and safety, and between the pilot's attitude and safety. How many eggs do you want to put in that basket? The choice is yours

1 comment:

hawk205 said...

not exactly On Topic but related. Have you seen
http://www.miamiherald.com/multimedia/news/deadlyexpress/partone/index.html

Sure would be interested in your comments