471–480 of 675 posts
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This only holds true if you’re flying at or above the transition altitude. The transition altitude depends on where you’re flying: for example, in the USA and Canada it’s 18_000 feet MSL.
It's still sea-level. The transition altitude just changes the altimeter setting from one that matches the current air pressure to a standard pressure setting.
“According to this data, the plane’s altitude was only fluctuating by about 20-30 feet. This is more stable than I expected!” Autopilots are very good and they are servoing to the pressure altitude. Many pressure altitude encoders used in modern aircraft (for example to drive altitudes that transponders report to SSR radar or via ADS-B) have 25 ft encoding resolution. That 25ft resolution is likely what is being seen…
I have read somewhere that so much precision could actually be dangerous in some circumstances. This is because this way, if a pilot goes 3000 ft for instance, it will be exactly 3000 ft, if another pilot also wants to go 3000 ft on a collision trajectory, it will be a guaranteed collision. When altitudes are not that accurate, there is a higher chance it being just a near miss. The solution, I think, was to simply a…
“According to this data, the plane’s altitude was only fluctuating by about 20-30 feet. This is more stable than I expected!” Autopilots are very good and they are servoing to the pressure altitude. Many pressure altitude encoders used in modern aircraft (for example to drive altitudes that transponders report to SSR radar or via ADS-B) have 25 ft encoding resolution. That 25ft resolution is likely what is being seen…
I have read somewhere that so much precision could actually be dangerous in some circumstances. This is because this way, if a pilot goes 3000 ft for instance, it will be exactly 3000 ft, if another pilot also wants to go 3000 ft on a collision trajectory, it will be a guaranteed collision. When altitudes are not that accurate, there is a higher chance it being just a near miss. The solution, I think, was to simply a…
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Conference hotels often soak the companies with booths for internet access. One place I did for my company demanded $1500 for 3 days of internet access for up to 5 devices. In-room, you get free internet access, but in the windowless ballroom with spotty cell-service, there's nothing available for free.
I’ve also seen the opposite, where in-room Wi-Fi was charged, but in the hotel’s function spaces, it was free. The economics of this are confusing, at best. I have also had the situation where the in-room wi-fi was so slow that using my phone as a hot spot was faster!
When my son was younger - maybe 9 or 10 or so, we were on a plane and he was using his phone and I looked over his shoulder and realized he was on the internet... but I hadn't paid for an internet plan. I said, "son, how are you using the internet?" He said, "oh, a kid at school showed me - if you go here" (he opened up the wifi settings where the DHCP assigned IP address is) "and start changing the numbers, eventual…
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RVSM is overwhelmingly about instrumentation accuracy and precision, not pilot capability. [0] The pressure difference between 5K MSL and 10K MSL at standard conditions is 14.6 kPa. The pressure difference between 30K MSL and 35K MSL at ISA is 6.3 kPa. For a given amount of aircraft-to-aircraft variability in their precision altitude sensing equipment, the resulting difference in actual altitude is more than double i…
Still missing the point. You’re talking about getting different aircraft to agree between each other. The post upthread expressed surprise at an aircraft maintaining a steady altitude to within tens of feet. That’s been a thing for many decades.
For autopilots servo'd to pressure altitude, holding altitude to within 0.02 kPa is more difficult than holding altitude to within 0.05 kPa or to within 0.30 kPa (which is roughly the private pilot checkride standard as-tested).
Modern autopilots are actually better at holding altitude to a very tight tolerance than ancient, analog autopilots. Both can hold standards well within the PPL ACS.
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In the article above, in-flight wifi has an API reporting position, altitude, and velocity. That is a feed from avionics, which renders the claim of airgapped systems essentially null.
They could, for the sake of a ridiculous but clear example, have a display hooked up to the avionics and a camera hooked up to a separate computer which reads the values. There are various ways of connecting systems while physically guaranteeing one way data flow—a fiber optic link with the transmitter removed from one end and the receiver removed from the other is basically a less silly “camera pointed at a display”…
I want to see someone build a proxy that uses the free iMessage or WhatsApp allowed connection to send arbitrary data. Like have a WhatsApp relay set up at home that you are sending messages to and from, from the plane. Like at a most basic level, send a message of a URL to your home WhatsApp which loads the web page there, and sends the HTML back as a WhatApp message reply so you can render it etc. Wonder what someo…
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> There's this iOS app called Flightly I guess it's Flighty ( https://apps.apple.com/us/app/flighty-live-flight-tracker/id... ) I love that people are into this. In the days before iPhones, I had "Microsoft Streets and Trips" + a USB GPS unit + Laptop. It was fun having it on a flight and seeing movement data in realtime. It was less fun answering questions from people who thought looking at the GPS data was somehow…
I used to do that also. Way before cellphones, I'd bring my 2m radio on the plane and make contacts on simplex. That was fun to throw your callsign out and say "aeronautical mobile".
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Still missing the point. You’re talking about getting different aircraft to agree between each other. The post upthread expressed surprise at an aircraft maintaining a steady altitude to within tens of feet. That’s been a thing for many decades.
I think you're at least partially missing the point. For autopilots servo'd to pressure altitude, holding altitude to within 0.02 kPa is more difficult than holding altitude to within 0.05 kPa or to within 0.30 kPa (which is roughly the private pilot checkride standard as-tested). Modern autopilots are actually better at holding altitude to a very tight tolerance than ancient, analog autopilots. Both can hold standar…
"more" difficult is obviously true, but the difficulty of holding an altitude is only a small part of the overall difficulty of RSVM.
In other words, RSVM is much more about accuracy than precision, and the claim was that planes were "probably fairly precise already". The reason they needed upgrades was to improve the accuracy, not so much to improve the precision.