VBprogrammer

198 ms·

2011.
by VBprogrammer 8y ago
As a Scot myself, living in London, I've more than once longed for the regulations that we had in Scotland. Even simple things like not being able to charge random fees makes it much easier to compare two or more properties on level te
2012.
by VBprogrammer 8y ago
I think it can work fine so long as there are sufficient protections for renters. Rent control, long term contracts etc. I understand that this is the case in Germany. Unfortunately this works by making property less attractive to investors
2013.
by VBprogrammer 8y ago
Yeah, I can imagine. I mentioned elsewhere, the previous flight managed to develop a reasonable mental model (they thought that the Mach Trim System was responding to a wrong airspeed input). Saying that, failing to guess what's going
2014.
by VBprogrammer 8y ago
Also worth noting that the reason we don't simply scale the forces down to the point a pilot could easily handle them is that above manouvering speed an aircraft can be damaged by full control deflection.
2015.
by VBprogrammer 8y ago
> - My first / immediate thought is that my previous action led to an undesired aircraft state. FYI This is shown in the Lion air preliminary report. They select flaps 0 (from flaps 5) and a few seconds later reselect flaps 5. Unfor
2016.
by VBprogrammer 8y ago
I just had a better look through the graphs in the report and I can see exactly what you are talking about. There is a clear pattern of trimming against the MCAS, then just before the speed increases and the altitude decreases the pattern c
2017.
by VBprogrammer 8y ago
FYI It does look like the graphs here indicate "pitch trim position" which I believe is the absolute value. https://reports.aviation-safety.net/2018/20181029-0_B38M_PK-...
2018.
by VBprogrammer 8y ago
I haven't checked but I'd bet STS is speed trim system (Aka Mach trim). Interesting that he came up with a reasonable mental model of what was wrong even though Boeing hadn't given them any details.
2019.
by VBprogrammer 8y ago
Anyone who's ever piloted an aircraft would try to re-trim against pitch forces. It's inconceivable that the pilot for some reason just failed to do that. I'm not sure exactly what force it takes to get full nose up elevator
2020.
by VBprogrammer 8y ago
A potentiometer (or something fancier) directly attached to the stabilizer would do it. I'm not sure if they do have one or not. They rate of movement on the stab trim is different depending on the source of the trim change so it'
2021.
by VBprogrammer 8y ago
There is a trim position indication. It's to the left and right of the throttles. It's a critical thing to check before starting the takeoff roll. You can see it on the copilot's side here by the trim wheel. http:/&#x2F
2022.
by VBprogrammer 8y ago
It's running for 10 seconds at a time for 2.5 units of trim out of a possible ~15. That's quite a big trim change. I find it hard to believe that it's not noticed because of the 'boiling a frog' situation. It not po
2023.
by VBprogrammer 8y ago
> The difference is that pilots had been trained and have flown the old one for many years and trained to avoid the unstable conditions for the old 737. I don't think that's the case. MCAS was added to satisfy a requirement in
2024.
by VBprogrammer 8y ago
> Also in full fly by wire aircraft there is a "red button" There is no red button as such (at least as far as Airbus is concerned). The computer decides that something has gone wrong and invokes an alternative law. You'd
2025.
by VBprogrammer 8y ago
I don't think disabling MCAS (or electric stab trim) should be routine. Given most airliners have given up putting trim wheels in the cockpit I'm sure the reliability of electric trim is very high. Reading between the lines this s
2026.
by VBprogrammer 8y ago
Most of those knobs below the glare shield are things like dimming the displays, setting what appears on each display (notable as there was an AIRS report from a pilot who struggled with the displays and presentation). But the key controls
2027.
by VBprogrammer 8y ago
Do you have a citation for "incorporated because the plane...has a chance of facing a stall at lower speeds than earlier 737 variations". I think you may have misread something. Normally stalling at a lower speed is a good thing.
2028.
by VBprogrammer 8y ago
I'm not sure where you draw the line though? None of this is new, making modifications to existing designs is the aviation equivalent of developing a new feature. Hanging new engines from an existing fuselage, replacing the avionics an
2029.
by VBprogrammer 8y ago
It's probably splitting hairs at this point but I don't think that MCAS was nessasary to avoid having different training requirements between the NG and the Max. The Max may not have been certified without MCAS. The existence of M
2030.
by VBprogrammer 8y ago
> The short answer to your first sentence is that MCAS was needed in order to make the MAX so similar to the NG versions that it could be claimed that no additional training was needed. I think that places the emphasis in the wrong place
2031.
by VBprogrammer 8y ago
> Why is MCAS needed? If the MAX is so similar to old 737’s and no additional training is needed, then why the MCAS? The most relevant question is “is the MAX aerodynamically stable?” If it is, why do we need the MCAS? That needs to be i
2032.
by VBprogrammer 8y ago
Often times as a Software Developer I encounter a bug which has an obvious two line fix. Rather than implementing that though I often spend another few minutes digging into how and why that bug was introduced. Often times I'm left with
2033.
by VBprogrammer 8y ago
You make a couple of very good points. And your right, if it were that simple they hopefully would have described it that way. In general pitch trim runaway incidents are easiest to control at low speeds. It gives you more aircraft configur
2034.
by VBprogrammer 8y ago
Unfortunately I think you may be misinterpreting that section in the manual. From your senario when the trim moves nose down. You apply nose up on the elevator which makes the trailing edge of the elevator go up which applies a downwards fo
2035.
by VBprogrammer 8y ago
> You seem very convinced that MCAS is some trivial system when it is very clear physically and legally speaking that that +/- 2.5 degree stabilizer movement at the right time is what the air-worthiness certification is dependent on
2036.
by VBprogrammer 8y ago
Perhaps it's just because I've been trying in vain to make similar points but I don't understand why you've been down voted here. It seems the only acceptable response is that Boeing deliberately killed people by trying
2037.
by VBprogrammer 8y ago
Ok let's look at it another way. Do you think it's even remotely likely that Boeing haven't had one of their 737 Max aircraft try this out at a safe altitude? They staked the future of the aircraft by saying they believe they
2038.
by VBprogrammer 8y ago
I've seen that before. It certainly doesn't say it's impossible. I need to have look in the certification requirement but I'm pretty sure it would be uncertifiable if the trim couldn't be neutralised.
2039.
by VBprogrammer 8y ago
It literally went from a "steam gauge" aircraft to glass panels before. There are aircraft which are much more different and are on the same type rating, for example the 757 and 767. That's literally a widebody and a narrow b
2040.
by VBprogrammer 8y ago
That's fair. It would be interesting to find out whether it was an existing sensor, used on other aircraft, and what the reliability is like. But I doubt that information is readily available.

More ›