Thursday, March 28, 2013

Are you an Autoflight Junkie?

Autopilots have been around for a while now.  Amazingly, the first aircraft autopilot was developed by Sperry Corporation in 1912!  I seem to have missed the hundreth birthday of the autopilot somehow.
Two decades ago the autopilots on most airplanes still weren't all that hot. They could hold a heading and altitude pretty good, and track an ILS when things were tight. Tracking a VOR radial was like doing S-turns down the airway. The button for airspeed/mach hold looked better than it worked. Most pilots in the 727 days hand flew the airplane up to altitude, and were hand flying it for most of the approach. Autothrottles? Forget about it!
You knew power settings and pitch attitudes for every phase of flight - you had to!
Along with the digital computer revolution came autopilots and auto thrust systems that truley lived up to their names. Inertial Navigation Systems (INS) evolved into Flight Managment Systems (FMS), and GPS made the prospects of manual updates, plotting, lines of position, and all manner of once-necessary long range navigation techniques quaint.
There is not doubt that these fine systems have made possible many things that were not possible - at least not safe - using the old methods. Think of RNP approaches through mountain passes, category III autolands,  RVSM separation above FL290, RNAV arrivals and departures; plus the advances in communication: SATCOM, CPDLC, and the many flavors of ADS.
But where is the line between using these systems as assistance, and dependence on them? When the autopilot is on for all but 5 minutes of a 12 hour flight, how are manual flying skills maintained? When pilots are virtually afraid to turn off the autothrottles, what happens if those systems fail?
When you follow the flight directors, do you look beyond the bars to see what pitch attitude is being commanded? If the flight directors suddenly went away, would you know what pitch attitude to set? For climb, cruise, descent? How about power settings.
What if the airspeed indicator we use for pitch guidance in constant power climbs and descents stopped working? It's easy if the A/S flag pops out, or your instructor slaps a sticker over the airspeed indicator, but what if it was just a little higher, and then a little more, and slowly, a little more?  Would you notice if your airspeed were unusually high for the pitch and power you have? How far off would it have to be before you could tell? Without an operating airspeed indicator can you tell the difference between a low speed buffet and a high speed buffet? What are the sounds, how does it feel? Is that stall warning real?
Even with all the magic, don't forget to click it all off and fly the airplane on a regular basis. Pay attention to those pitch and power settings, they may save your bacon some night.
When we look at accidents like AF 447, we see that when the autopilot, flight directors, and autothrust went away, control of the airplane was lost very quickly. It's likely that it comes down to the pilot flying not knowing what attitude to fly. When the flight directors came back on in a mode matching an inappropriate climb rate they were likely followed. One and a half minutes later they would be falling at 10,000 feet per minute the stall warning having sounded constantly for the previous 52 seconds.
The automation is great. But, don't let it be the only way you do fly, or can fly the airplane.
Don't be an autoflight junkie.

No comments: