Mac McClellan of Flying magazine nailed it this month. Mac wrote about autothrottle systems and the tactical advantages they provide. He also exposed that Southwest Airlines, whose flying practices have stirred my gut before, does not use the autothrottle systems installed in their fleet of Boeing 737 jets. Southwest says the reason for their disuse of autothrottles is because it helps to "keep the pilots in the loop." That's simply foolish. That's what the N1 and airspeed indications are for.
Mac had a great comeback for this. He suggested Southwest discontinue use of their entire autopilot system, including lateral and vertical navigation modes, in order to really keep the pilots in the loop. More like in a spin.
Humans fail constantly. A staggering majority of aircraft accidents (airline included) are caused by pilot error. Cockpit automation rarely fails. It is highly reliable and precise, and offers tremendous enhancement to flight safety by backing up the human pilot. That's the idea behind autothrottle systems. Airspeed control is higher priority than lateral, or even vertical navigation. Autothrottles provide overspeed and, more importantly, underspeed protection during all phases of flight. This is especially critical during approach and landing when airspeed is low and pilot workload is high. Just look at the crash of Colgan 3407. The Dash 8 wasn't equipped with autothrottles and the captain failed to add power after the airplane leveled off at an intermediate altitude on the approach. A stall and horribly botched recovery resulted in a spin and loss of life. An autothrottle system would have prevented this accident.
Southwest just doesn't get it. I think it will take a stall/spin accident of one of their 737s before Southwest recognizes and embraces the importance of using autothrottles, especially on heavy, high performance jets. I'm not sure if this is still true today, but I once read that Southwest didn't use their autobrake systems either. It's that "cowboy" attitude that concerns me. Boeing installed these systems in their airplanes for a reason. They should be used.
