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cliffardus

Why can't a woman (an FMC) be more like a man (a human)?

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My apologies to Henry Higgins for the Topic Title......

 

Why does the FMC sometimes need a pilot to land an aircraft?  Surely it has all the relevant information that the pilot has when making an approach and landing?

 

So why should it sometimes be necessary for a human to bring the aircraft to a safe landing?

 

With computer science now so sophisticated I find it difficult to think of an explanation.

 

Cliff 

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So why should it sometimes be necessary for a human to bring the aircraft to a safe landing?
 
With computer science now so sophisticated I find it difficult to think of an explanation.

 

Until you get an obstruction on the runway (aircraft, vehicule, animal) or something interferes with the ILS signal...

On a serious note, the computer are still to rigid and not able to improvise when an unexpected situation comes. And the autoland system of an aircraft is not able to detect situations where landing is unsafe.


Romain Roux

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Avec l'avion, nous avons inventé la ligne droite.

St Exupéry, Terre des hommes.

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Why does the FMC sometimes need a pilot to land an aircraft?

 

With all due respect, this idea is so incredibly backwards that I find that it is imperative that someone steps in to correct this: it's not only 'sometimes' that the pilot lands the aircraft, it's most of the time. The mentality that the plane flies itself is partially the cause of people viewing pilots as an unnecessary evil up front, which is not a good image.

 

The autopilot is not there to do your job for you. It has always been a tool to assist you in accomplishing a task, and nothing more. Granted, that assistance can be used for quite a lot of the flight, but it's your job for that entire time.

 

 

 

Granted, just about any competent programmer could program an aircraft to get from one point to another. With a little more effort, one could program an aircraft to be able to accept a variable route to go to different destinations and other inputs. Programming for what you expect is the easy part of programming, though. It's programming for the unexpected that's the difficult part. What happens if you need to get vectored? What happens if you get re-routed? What happens if there's an in flight emergency? You can program in a ton of different scenarios, but I can guarantee that there will be one day where the program will get something that it doesn't like, and then a couple hundred people are gone because people thought that pilots were worthless. That's a tough lesson to swallow.

 

I know you didn't say that pilots should be out of the flight deck, but discussing the pilotless aircraft can help you understand the answer to your question: pilots need to be up front to take care of things that programmers couldn't even imagine. Look at United 232, as an example. Designers thought that they had a fail-proof system in the fact that they had a triple-redundant hydraulic system, but they didn't expect a scenario where something would sever all three lines at once, so all three lines were run in close proximity. Well, the number 2 engine came apart, and what do you know...an ejected fan disk severed all three lines. The resulting situation required the ingenuity of three members of the crew (captain, FO, and FE), along with a DC-10 instructor pilot, to get the aircraft into a semi-controllable situation using engine thrust. From there, they were able to coax it onto approach and attempt to land. The attempt was not fully successful, but their actions were credited for saving lives onboard. A computer couldn't teach itself that, or branch out into trying new things to see if they might fix a situation. There are a few other situations where pilots used alternate means of control to bring an aircraft back down safely. As much as you can program functions to attempt to handle situations like that, there will always be some unknown out there that a human can handle that a computer simply couldn't.

 

Okay, so it's been made clear that pilots should be up front, but I haven't really touched on the landing bit. One of the most important parts of a flight is putting the aircraft back on the ground. The only currently approved method for landing an aircraft is utilizing autoland on an ILS (CAT doesn't technically matter). While it's pretty rare that a major airline flies into an airport without an ILS (at least in the United States and much of Europe), there are several instances where approaches do not have an autoland option. DCA, as an example, has a charted visual when landing south, which needs to be flown by hand. While there's an RNAV RNP approach that the autopilot can fly for you, it needs to be completed with a hand landing. Even the LDA approaches (essentially an offset ILS) require you to land the aircraft by hand when landing to the south. There are vast areas of the world that require you to fly VOR and NDB approaches, which have no vertical guidance for the autopilot to use. Those cases definitely require hand flying skills.

 

Even with all of that technology, though, it's imperative that pilots remain competent at landing the aircraft so that they can do so if things were to go wrong with the automation. Take Asiana 214 as an example. The glideslope on the runway they were assigned to was NOTAMed out of service, which meant they got no vertical guidance. The pilots were so used to coupled approaches (approaches with the autopilot) that their ability to hand fly the aircraft was compromised. It was so rare for them to actually fly the aircraft themselves. This led to a discomfort in that practice (flying by hand) to the point that the pilots left the aircraft in improper autopilot modes, contributing to the crash. Had the pilots simply taken control over the aircraft, with the appropriate hand flying skills intact, it wouldn't have been an issue. Instead, much like simmers, they were more concerned with trying to get the automation to continue doing a job for them instead of just taking over. As someone who worked at a flight school who trained the pilots of this region, it was a concern we had for quite some time, though that area of the world is not the only place that this concern exists - there are several operators that suggest or require autopilot use as soon as possible after takeoff and as late as possible for the landing. The DOT, as an example, recently slammed the FAA for not including policies requiring airlines to keep pilot skills sharp only a few weeks ago. The issue here, though, is not as inherent to the culture as it is elsewhere (I know some people will not like that statement, but a little research into human factors in accident investigation paints a very clear picture related to cultural expectations).

 

As such, despite the simmer belief that autolands are the norm, and the plane lands itself most of the time, this is simply not true. In fact, it's quite normal for maintenance or OPS to get a little pushback when they request that the crew let the plane land itself for aircraft currency requirements, at least at major carriers here in the States. The only time it really, absolutely gets done, is when the weather is just, that, bad, requiring a CAT IIIb approach (and even then, some airlines have substituted a HUD for maintaining an autoland system, like Southwest, so the pilot still land by hand in CAT IIIb weather).

 

 

 

It's entirely possible for the aircraft to land itself from a technical standpoint. Despite RNAV not being approved for autoland at the moment, that's more from a regulatory standpoint. It isn't too technically difficult to activate autoland for RNAV. One must keep in mind, though, that pilot skills must be maintained, and that comes with continuing to fly by hand, which comes from using the autopilot less often, particularly for landing. Otherwise, if the automation were to die out, as it has either partially or fully in the past, we're left with pilots with skills not up to the task of the requirements of the situation.

 

You aren't up front to sit and observe. You are up front to be in command. Your skill set must go beyond the AP, such that the AP only assists you with your job. If it's the other way around, you need a new career because people are counting on you and your crew.


Kyle Rodgers

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Kyle.......that's just the answer I needed. It's Interesting and informative and I thank you.

 

You guys really earn your living. Quite apart from living away from home for extended periods the responsibility must be formidable. I reckon the rest of us just don't know what stress is compared to what you must face when things go wrong.

 

Thanks again for taking the trouble to deal with your answer as you did.

 

With my regards,

 

Cliff

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