No, this isn't about A-10s or airliners turned into bombers (it never works well). It's about what happens when the automation we take for granted turns around and bites us.
We're climbing out of Newark the other night with a full load of, well probably flowers since Valentine's Day is coming up.
We're late because of the high freight volume (good problem to have) plus a long conga-line for the deice pad. It's sometime around 5:00 AM and I'm halfway through what's going to be a 12 hour work night.
It's a typical winter night on the East Coast. We're in and out of the clouds all the way up past 30,000 feet. It's the Captain's leg and I'm busy dealing with the multiple New York Center frequencies while he flies. We've long since coupled up the autopilot and the trusty 757 is fully automated in LNAV (lateral navigation) and VNAV (vertical navigation).
LNAV means the autopilot is flying a pre-programmed route across the ground. VNAV means it's flying its most efficient climb profile. We're cleared to 36,000 feet and it will automatically level off when it gets there. So far so good. This stuff is awesome when it works the way it's supposed to.
That's when "it" happens. I've seen "it" once, maybe twice before in my 5 years on the 757 and I still don't know exactly what causes it.
At our current weight and altitude, with full climb power, we should be climbing somewhere in the range of 1500 to 2000 feet per minute. The Captain has his head turned looking at one of the electronic charts when I notice the nose come up to about 10 degrees nose high and we "peg" the needle on the vertical speed somewhere around 6000 feet per minute. Impressive, except it shouldn't be happening. I also start thinking that I've maybe seen this once before.
Mind you at this time of morning I have maybe three working brain cells and I'm using two of them to breath with. The mental gears are turning but they're turning slowly. My mental processor works its way from "hmmmm that's odd" to "I don't think it's supposed to do that".
I don't really know what caused this condition. A strong updraft or wind shear might cause it but we've have probably felt that since there's usually turbulence associated with it. It's possible that VNAV got a little fast on the airspeed, "thought" it needed to slow down and pulled the nose up.
The 757 has few vices, but the autopilot is one of them. It's designed not to spill the passenger's drinks so it only has so much pitch authority to move the nose up and down. Especially down, since most people don't enjoy feeling the plane push over like a roller coaster.
This is what's about to bite us. The nose is up much too high. At sea level we'd be doing our best impression of an F-15 right about now but at 30,000 feet we don't have that kind of thrust. Something has to give and in this case it's the airspeed, which starts rolling back quickly. The autopilot figures out something's wrong but it's waaaaay too slow. I see us get 10, 20, 30, 40 knots slow and the speed is decaying quickly. I'm now in "something is definitely not right and we need to do something about it" mode.
The engineers were thoughtful enough to put a little yellow indicator on the airspeed tape that shows our stall speed. Right now the yellow "hook" is sitting right at 200 knots and the airspeed is somewhere between 240 and 220.
All this took place much more quickly than it took me to type this. I said something like "Hey! Watch this thing! It's got the nose way up!". Actually at 5:00 AM it might have sounded more like "Mongo think nose too high". Either way I got the Captain's attention.
Since the engines are already at full climb power the only way out of this is for the nose to come down. The first step when the automation starts acting weird is to "dumb it down" - go to a more basic mode. He hits the button for "Vertical Speed" and spins the dial down to 500 feet per minute. This is the most basic mode of the 757 autopilot. It will fly a given speed and climb/descent rate but it still can only react so fast.
This is a good move but we're too far out of bounds at this point. The autopilot just isn't going to get the nose down before we run out of airspeed. The next step is to turn the automation off and he does exactly that. Do some of that pilot shit Maverick!
We get the nose down to almost level flight and sloooooowly start regaining our lost airspeed. We're far enough behind the power curve at this point that we can climb or accelerate but not both. Once we get things back inside the lines we re-engage the autopilot and uneventfully make our way up to cruise altitude.
The Airbus 300 flight management system used to "go stupid" more often than the 757. The Boeing is roughly a generation newer and has a faster processor. I recall being told that the A300 was roughly equivalent to a Commodore 64. We used to joke that new Airbus pilots would say "What's it doing?" while seasoned ones would say "There it goes again!".
In some ways that makes the 757 more insidious. When I was an instructor pilot I was told "It's the good student that's going to kill you". The 757 works pretty well so it's easy to get complacent with it. It works great - right up until that one time when it doesn't.
Now I'm really not an anti-technology Luddite as some have claimed. I may be a knuckle-dragging B-52 driver but I think automation in an aircraft is generally a plus.
I'm also not a starry-eyed "technology is always awesome!" technophile. I think the world would have gotten along just fine without the invention of Sarin gas, the W53 thermonuclear warhead and Windows ME, in no particular order.
I'm of the "technology is cool but it can be a mixed blessing" school of thought. Automation in the cockpit can reduce a lot of drudgery and free me up to look at the big picture. It can also help the plane fly the most efficient climb and descent to squeak out every last bit of fuel savings. It's great when Chicago Center gives you a clearance like "Be at 16,000 feet 30 miles west of Dupage". It takes a lot of the guesswork out of the job.
The problem with technology is that it's never perfect. Nothing designed and built by humans is. It can also lull you into a false sense of security. Finally, if you depend on it too much you start losing your basic piloting skills. I'm not the first person to worry that we may be raising a generation of "automation cripples" who won't know how to hand-fly a jet.
In my opinion, the key to using automation in the cockpit effectively is:
1. Know how it's supposed to work.
2. Monitor it to make sure it's working the way it's supposed to.
3. If it isn't, switch to a more basic mode of automation.
4. If that still doesn't fix the problem, turn it off.
I'm still the pilot and it's my job to make the plane go in the direction it's supposed to go.
I can think of at least three recent accidents where automation was a contributing factor. Air France 447, the Asiana 777 in San Francisco, and the recent AirAsia flight. Note that I'm still researching AF447 and plan a more in depth look at that particular incident.
This doesn't just apply to aircraft. Automation is creeping into everything, like it or not. If you drive a new-ish car it's likely far more automated than one from ten years ago. They will only get more automated in years to come.
Have you ever mashed the brakes hard enough to engage the anti-lock? Do you know what the anti-lock feels like when it works?
Have you ever disengaged the traction/stability control? Did it drive differently?
Does your car have any other automated systems like adaptive cruise control? Do you know how they work? Do you know how they might screw up and what it would look like?
In short: have at least a basic knowledge of how the automation works. Nobody expects you to be an engineer but at least know what's supposed to happen when you flip the switch. Then keep an eye on it and be ready to shut it off if you need to. Complacency kills.