Here’s a great story published today on the GPS World website about what happens when an aircraft loses all electrical power and ‘goes dark’, leaving the crew unsure of their position on a long over water flight. The navigator’s solution? Pull out the airplane’s bubble sextant and start taking readings to calculate a line of position!
(Just click on the image to open the article)
Based on the author’s description of the event and his mention that the GPS equipment racks were in-place but the units were not yet installed I’m guessing this incident occurred sometime in the very late 1980’s or early 1990’s. It’s a fascinating tale of how old analogue equipment and basic navigation skills, mixed with a little educated guesswork based on experience, can save the day.
Think this same thing can’t happen today? Think again. Modern aircraft are little more than computers with wings, and the number of points of failure on these ‘systems’ are exponentially greater than older aircraft. Not only can a modern aircraft experience a complete loss of power, it will happen at some point. It’s all a matter of odds. When the odds are against you the electrons will stop flowing. Then what?
The author interestingly contrasts this experience with what would likely happen today. Crew members would pull out handheld GPS units or smartphones and the plane would safely navigate to its destination with little drama beyond an ass-chewing for the maintenance team and some great bar room “There we were at angels 20…!” stories. But like modern aircraft, GPS receivers and smart phones require electricity to run. Let’s hope everybody charges up before boarding the airplane!