The issue at stake here is not the pitch servo, but the pitch trim servo.
Most aircraft, light or not, are not designed so the pilot (or the autopilot, for that matter) can use elevator to maintain control in a fully out-of-trim condition. That is what is being discussed in this thread drift, that I fully take responsibility for. Plse @mod feel free to move to a new thread like “pitch trim runaways”
Peter wrote:
That is true for all airliners. They have a large speed range and thus have a large trim range.
It’s not about the range, it’s about the inability to move the trim by hand. The 737 is the only airliner I am aware of which has this “feature”.
RobertL18C wrote:
in light GA the pilot should be able to overcome the pitch servos, even on a one Weetabix breakfast :)
Absolutely. Yet, the startle factor and figuring out what is actually happening can be pretty “exiting” particularly if you are at low altitude.
Agree about the thread drift. In the end however it does not matter why you remember that something is important but that you remember. The trim issue and verifying where the cut offs are have been quite popular in discussions after those accidents. And I am aware of at least one GA incident where a stuck trim switch of similar design than in the OP’s plane (i.e. not original split switch) caused some rather interesting recovery when it went all the way nose up on short final….
but it is not a law of nature that stabilators with a large trim range are impossible to trim by hand if the stabilator is under load
With enough servo assistance…
But maybe not structurally possible to be severely out of trim while flying at a speed which is way outside the trim range. Think of the elevator trimmer forces if you are say 200kt too fast.
https://www.aerosociety.com/news/downfall-the-case-against-boeing-reviewed/
Boeing troll. I’m surprised they keep bothering.
johnh wrote:
Boeing troll.
Really? Some pertinent extracts from the above. Please tell me where this is a troll’s makings:
…
And even today you do not need a dedicated 737-MAX simulator to demonstrate an MCAS runaway, which looks very similar to any other runaway of the trim and is resolved the same way.The fact that MCAS wasn’t in the manuals? It should have been of course but did it make any difference? Not one bit, since the average line pilot doesn’t possess an intimate knowledge of the systems that operate silently in the background. If you doubt this just ask any airline pilot you know well enough, to describe how anything ‘behind the scenes’ works on their aircraft especially if it is a Fly by Wire type! They will probably say they don’t know and don’t need to know. And that is true. In any event, both failures that occurred were Memory Items requiring no systems knowledge whatsoever. That is why they are called Memory Items. You perform them right away from memory with no reference to manuals.
…You can still turn a 737 upside down if the mood takes you – it’s a real manual aircraft in every respect and has very few FBW (Fly By Wire / AR architecture) built-in defences against poor flying skills, as seen on every aircraft designed in the last 30 years or so. Does every operator know that, or do they think a 737 is a Boeing version of the Airbus A320 series? Are they told this when they buy them? It’s important to know, but does this make the 737 a bad aircraft? Not at all. The 737 was and remains one of the finest aircraft ever built, and will remain so for many years to come – perhaps 70 years from its first flight. You just can’t take short cuts with the training of any airline pilot and especially not on an aeroplane which under all the fancy electronic wizardry is a very basic aircraft that can still fly with no computers working at all. You just have to know how to do it. Old-fashioned nonsense? Many think so, which is why I have written this piece!
…
Can automation solve these problems, because many believe that this is the solution rather than the expensive alternative of more extensive training?
…
Boeing troll.
Well, the article is exploring a seriously non-PC area, but ask yourself why didn’t Ryanair crash the 747 MAX too…
Sure they did some crap software, but so have Airbus, only Airbus got away with their various cockups.
Well, mostly, and a) they have skilfully managed the discussion of where they didn’t and b) they have the luxury that the type is made in the same country where the BEA resides 
Anyone doubting point b) should read Concorde by Mike Bannister.
Anyone who has shared a cheap hotel with a load of FTO students from [a non-PC list of countries] will understand perfectly why they might have thought a 737 is FBW.
Disclaimer: I am not running for any public office 
Peter wrote:
With enough servo assistance…
That is exactly the way A320 and later Airbus aircraft are designed.
However, that does not stop trim runaway incidents+accidents from happening if you have a crew acting as if improperly trained (not only the MAX’s with “third-world-crews (*)” but, for example, the loss of the XL Airways Germany A320 in Perpignan , whose only saving grace was that there were no pax onboard)
( * ) For failure of a better prejudiced descriptionThat is exactly the way A320 and later Airbus aircraft are designed.
Correct me if needed but in a fully manual mode (no software protection) an Airbus will also not fly if trimmed way off the actual speed.
the loss of the XL Airways Germany A320 in Perpignan
Well, an Airbus (or any other civil aircraft AFAIK) does not have obstacle clearance protection (as Germanwings showed)
XL airways lost control due to trim runaway, after a too-low stall recovery crashing into the sea… and again had the crew followed trained procedures, they need not have known what caused the runaway and would have saved the flight.
@Mooneydriver (or anyone else for that matter) not that I am advising that you do, but have you ever tried to move manually or electrically the pitch trim in a Mooney while flying severely out of trim?
Full disclosure: I personally have not.
