Landing the max

[yycflyguy]

Why Weight on Wheels doesn't automatically trigger A/T Retard is beyond me. "New" airplane. Dumb logic.

That would be to avoid a false signal retarding the thrust levers at an inappropriate time such as in cruise or intercepting the ILS.

When would you have weight on wheels during cruise or intercepting glideslope?

[Eric Janson]

Why Weight on Wheels doesn't automatically trigger A/T Retard is beyond me. "New" airplane. Dumb logic.

That would be to avoid a false signal retarding the thrust levers at an inappropriate time such as in cruise or intercepting the ILS.

When would you have weight on wheels during cruise or intercepting glideslope?

A/T system works with inputs from various systems. A false Radio Altimeter signal has caused an accident by retarding the thrust levers on the ILS and keeping them at idle while the speed decayed to Vref - 40.

Adding complexity also adds to the failure cases that need to be addressed - in your example it would be a false wow signal with all the consequences. That could come at any point during the flight.

It's far simpler not to have your suggested feature.

Adding complexity is not always the best option.

[yycflyguy]

So you're saying it's safer, compared to the unlikely event of a false radar altimeter reading, that the thrust levers (that you can see physically moving) should never depart from bugged speed than it is to have a microswitch sensing WoW for the thrust?

I would suggest that if a crew allows their energy state to decay to Vref - 40 that maybe Wow sensing is the least of their problem...

[Eric Janson]

Here's the accident. It's not that unlikely.

https://en.wikipedia.org/wiki/Turkish_A ... light_1951

(Turkish ALPA called the crew 'Heroes' and publicly blamed ATC )

The problem was that this failure wasn't in the FCOM and crews were unaware this could happen. I'm sure you'll find a bulletin about this in the current FCOM.

I've had the thrust levers of a 737 go to idle in cruise for no apparent reason.

Can be very confusing when systems don't work as expected - especially with no obvious failures.

[fish4life]

ummm, is that not a good example of why the working up north is great for teaching you lessons compared to the "European" model? They caught the fact it got slow initially but then what the hell happened?

[Eric Janson]

ummm, is that not a good example of why the working up north is great for teaching you lessons compared to the "European" model? They caught the fact it got slow initially but then what the hell happened?

This is more a case of failure of basic flying skills - monitoring your airspeed is one of the first things you learn when you start flying.

A lot of recent crashes have occurred because Pilots were unable to fly their aircraft after relatively benign failures.

As for landing the 737 - when I flew it it was "Manual flight = Manual thrust". Depending on conditions I would reduce the thrust earlier or later as required during landing.

The only time A/T was used was on an autoland.

Not sure why it needs to be any more complicated than that.

[Level Change]

No, we don't teach to "chop" the power at 40 feet. Power is reduced in the flare, idle at touchdown. Aircraft limitation is AT off by 50' unless doing an approach with both autopilots engaged, such as Cat2 or Cat3.

There is a note that allows deselecting of the speed tile to keep AT armed in the event of a GA but personally, I don't do it as it just complicates matters in my opinion. There are some gotcha's with that. This is just a 1950's airplane with lipstick, not particularly complicated but it is "old school".