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Reztes posted:Alright so the dude I moved the Grumman for is offering to sell me a 1/4 share of the plane and I was not expecting this. Seems possible it could be a good deal financially vs. continuing to rent club and flight school planes if I flew it in the neighborhood of 60-80 hours. Anybody have good resources for estimating expenses or how to otherwise evaluate a co-ownership deal like this? Call the AOPA. They've got numbers guys who will run everything for you (then try to sell you insurance).
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Nov 21, 2018 23:21
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CelestialScribe posted:See, this is the poo poo that scares the crap out of me: What bugs me the most about this is that the pilot even has to enter the air temperature at all. Apparently the plane has temperature sensors and a later software update allows it to automatically sanity check the pilot's entry against their own readings, but why doesn't it just use those from the start? Have a way for the flight crew to override it if the readings are insane for one reason or another, but when my cell phone has literally dozens of temperature sensors it seems like an airliner could easily have enough that they can sanity check each other, throw out insane readings, and average the rest with enough accuracy for the purpose. Being 1-2 degrees off isn't likely to cause a problem, but being nearly 70 degrees off definitely will.
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Nov 22, 2018 20:28
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It finally happened! I described to a new student how to do the landing flare, and then he did it! The first landing I helped out at the very end, and then the second landing was all him -- ever so slightly lacking in right rudder, but considering the uphill battle I've fought with some students to get them just to avoid flying it nosewheel-first into the ground, I'm well pleased. I don't know whether I'm improving really considerably as an instructor, or if I just got lucky with a good student, but drat! It's taken 5 or more hours in the circuit for me to get to that point with some of my other students. I can see this guy actually managing to get his PPL near minimums if he keeps going at this rate.
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Nov 22, 2018 20:44
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wolrah posted:What bugs me the most about this is that the pilot even has to enter the air temperature at all. Apparently the plane has temperature sensors and a later software update allows it to automatically sanity check the pilot's entry against their own readings, but why doesn't it just use those from the start? Have a way for the flight crew to override it if the readings are insane for one reason or another, but when my cell phone has literally dozens of temperature sensors it seems like an airliner could easily have enough that they can sanity check each other, throw out insane readings, and average the rest with enough accuracy for the purpose. Being 1-2 degrees off isn't likely to cause a problem, but being nearly 70 degrees off definitely will. When you're entering a flex temp, you're not entering the real temp therefore sensors can't help you; you're entering a fake temp to trick the engine into using lower thrust. And even then, the sensors may not be usable. For example, on the CRJ the temp sensors may have residual heat from being hated in the air on the last flight, so you can't use the info from them on the ground. The real temp is gotten by dispatch's computers from the NWS or wherever, and used by dispatch for the calculations, whereupon they datalink us the final results to enter into various places in the cockpit. vessbot fucked around with this message at 21:47 on Nov 22, 2018 |
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Nov 22, 2018 21:41
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Still, it seems like a total failure of HCI practice that the software doesn't go "hey, you just put in a value that's seventy degrees below what I'm reading as the external temperature. Are you sure that's right?" Like, if the temperatures disagree that much, then either a) you hosed up your input b) you are deliberately messing with the computer to trick it into doing something abnormal, or c) the sensors are reporting wrong data and in any of those cases the pilot should be alerted to take extra care. Also I would love to experience a full-power takeoff at -52C 
Sagebrush fucked around with this message at 22:06 on Nov 22, 2018 |
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Nov 22, 2018 22:03
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Sagebrush posted:Still, it seems like a total failure of HCI practice that the software doesn't go "hey, you just put in a value that's seventy degrees below what I'm reading as the external temperature. Are you sure that's right?" I wonder what the record for the LC-130s serving the South Pole station is. Daily mean temperature in March when they stop is -53C.
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Nov 22, 2018 22:13
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Sagebrush posted:
That's basically what an assumed temperature derate is though?
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Nov 23, 2018 02:35
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That's fine, but if the computer sees you derating the temperature by, say, more than twenty degrees it could pop up a warning saying "are you sure that's right?" How do you accidentally mistype "16" as "-52" anyway?
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Nov 23, 2018 03:10
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vessbot posted:When you're entering a flex temp, you're not entering the real temp therefore sensors can't help you; you're entering a fake temp to trick the engine into using lower thrust. On the 200s you still have to put in the OAT from the ATIS/AWOS. It’s a high quality aircraft.
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Nov 23, 2018 03:20
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e.pilot posted:On the 200s you still have to put in the OAT from the ATIS/AWOS. It’s a high quality aircraft. Doh! I even used to fly that. Chalk it up to traumatic memory suppression.
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Nov 23, 2018 04:18
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vessbot posted:Doh! I even used to fly that. Chalk it up to traumatic memory suppression. I always say the 200 is just as unpleasant to fly as it is to ride in. Can’t wait until it’s behind me.
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Nov 23, 2018 04:24
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e.pilot posted:I always say the 200 is just as unpleasant to fly as it is to ride in. The 200 is a piece of poo poo... but its MY piece of poo poo!
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Nov 23, 2018 04:37
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Desi posted:The 200 is a piece of poo poo... but its MY piece of poo poo! Hey now, that’s insulting to pieces of poo poo. 
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Nov 23, 2018 04:56
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e.pilot posted:Hey now, that’s insulting to pieces of poo poo. It’s poo poo after it hit a turbofan
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Nov 23, 2018 05:01
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Before or after said turbofan corelocked in a vain attempt to reach four ten baby
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Nov 23, 2018 05:38
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Yes with a dash of slow speed event.
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Nov 23, 2018 05:50
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Anyone remember that ATC who sounded like she was having a stroke... ... I heard that she had a .3 BAC by the time they got her tested..
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Nov 23, 2018 05:51
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e.pilot posted:On the 200s you still have to put in the OAT from the ATIS/AWOS. It’s a high quality aircraft. We have many computers on this ship, but they are not networked. Many fine men lost their lives just because someone wanted a faster computer, to make their job easier.
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Nov 23, 2018 10:27
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INTJ Mastermind posted:We have many computers on this ship, but they are not networked. That's what makes the 175 so great. The computers don't talk to each other. Even when they're supposed to. And yes, you have to enter OAT manually for takeoffs...on a plane that's 3 months old.
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Nov 23, 2018 18:37
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INTJ Mastermind posted:We have many computers on this ship, but they are not networked. All of this has happened before and all of this will happen again.
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Nov 23, 2018 18:43
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Sagebrush posted:How do you accidentally mistype "16" as "-52" anyway? +16C is approx 61F, and -52C is approx -61F, I’m guessing that the input was in F or something
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Nov 23, 2018 23:42
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So even if they entered the temperature wrong.... what keeps one of the pilots from saying “hey maybe we aren’t making this one” and aborting or firewalling it after lift off so you don’t fly low for two miles? I mean surely the thing had the power for it
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Nov 24, 2018 02:32
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Bob A Feet posted:So even if they entered the temperature wrong.... what keeps one of the pilots from saying “hey maybe we aren’t making this one” and aborting or firewalling it after lift off so you don’t fly low for two miles? I mean surely the thing had the power for it Premature Netflix deployment.
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Nov 24, 2018 09:42
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Bob A Feet posted:So even if they entered the temperature wrong.... what keeps one of the pilots from saying “hey maybe we aren’t making this one” and aborting or firewalling it after lift off so you don’t fly low for two miles? I mean surely the thing had the power for it This isn't the first time something like this has happened: "Air Florida Flight 90 cvr posted:15:59:35 [SOUND OF ENGINE SPOOLUP] From what I recall they flew all the way into the river with the thrust levers never going above about 50% travel despite the FO obviously having doubts about what was going on.
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Nov 25, 2018 16:22
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KodiakRS posted:This isn't the first time something like this has happened: Did they do that too? I thought it was icing on, well, everything that was the main cause of the wreck
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Nov 25, 2018 16:30
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hobbesmaster posted:Did they do that too? I thought it was icing on, well, everything that was the main cause of the wreck Sort of. Due to their "unique" deicing procedure there was ice on everything. Including the engine inlet pressure sensor. Since they used EPR to set their takeoff thrust they just moved the levers until they hit their target pressure and left them there despite every other engine instrument being nowhere near their normal takeoff indications. If they had set full thrust they probably would have had enough thrust to keep flying. That was just the last nail in the coffin though, they had made pleanty of dumb mistakes up to that point.
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Nov 25, 2018 16:55
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Swiss cheese model strikes again.
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Nov 25, 2018 17:50
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How do take offs for big airplanes work? Why wouldn’t they push to their temp/torque/whatever limit every time to ensure their is always enough thrust? In a land or FADECs why not just firewall it?
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Nov 25, 2018 19:16
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Most large airplanes normally take off with the engines producing less than their rated power, since it saves a significant amount of money from reduced engine wear, and most runway/load/temperature combinations don't require full power to meet the takeoff performance requirements. FADEC allows the engine to produce as much power as possible without exceeding temperature or RPM limits, but there's still a lot of cost savings in taking off at reduced power settings whenever possible. One of the nice things about FADEC is that it's typically smart enough to know if an engine quit, so it's pretty common for there to be systems that will either automatically run the good engine up to full power if one quits on takeoff, or it'll let the good engine produce more than the maximum rated thrust for a short time.
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Nov 25, 2018 20:22
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Bob A Feet posted:How do take offs for big airplanes work? Why wouldn’t they push to their temp/torque/whatever limit every time to ensure their is always enough thrust? Saving maintenance cost by keeping the temps down. Unless there are extenuating circumstances like possible wind shear, contaminated runway, etc., we use reduced thrust every time. Dispatch's computers upload our gross weight, bleed config, and anything else that affects performance, along with the runway we're gonna use, to a runway analysis provider (Aerodata in our case, another popular one is APG) where they crunch those factors against the runway length (or whether else may be limiting the performance: obstacles, drift down, etc.) and figures out the minimum thrust that will meet all those requirements and datalinks it to the cockpit.
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Nov 25, 2018 20:32
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Bob A Feet posted:How do take offs for big airplanes work? Why wouldn’t they push to their temp/torque/whatever limit every time to ensure their is always enough thrust? Prior to takeoff we calculate how much thrust we need to safely accelerate to v1, lose an engine, then either abort or continue the takeoff. This takes into account things like flap settings, weight, altitude, runway condition, anti-ice system, ect. Once we know how much thrust we need, usually in the form of a target n1 fan speed*, we set all the parameters into our FMS/FADEC and it will spit out a projected n1 value. If that value is significantly higher than required we reduce our thrust output by telling the FADEC that the outside air is warmer than it is. This causes the engine to produce less power reducing noise/fuelburn/wear during take off while still producing enough thrust. On the takeoff itself most FADEC equiped aiecraft have a detent for takeoffs and go arounds (TOGA). The thrust levers are placed in the TOGA detent either by the pilots or the auto throttles and the FADEC delivers the pre calculated takeoff thrust. Most aircraft have a system that will alert the pilots if the levers are not in the detent and a takeoff attempt is detected. In the event of an engine failure the FADEC will automatically go to max thrust on the remaining engines. In addition to this most aircraft have a "max power" detent for emergencies such as windshesr, stall, or if the FADEC does not recognize an engine failure. *N1 fan speed is the closest thing to a conventional tachometer that exists on turbofan powered aircraft.
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Nov 25, 2018 22:50
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Why does the FMS spit out the wrong value?
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Nov 25, 2018 23:10
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Sagebrush posted:Why does the FMS spit out the wrong value? if you put in the wrong performance reduction temperature, or if you input the wrong weights. The FMS is only as smart as the two retards sitting in the cockpit. It blows my mind how those two dudes can sit there before 80kts telling each other how it’s too slow and doesn’t feel right and no one thinks of idk maybe pushing the power levers up to max power?
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Nov 25, 2018 23:23
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Bob A Feet posted:How do take offs for big airplanes work? Why wouldn’t they push to their temp/torque/whatever limit every time to ensure their is always enough thrust? Air Florida 90 was a 737-200 with JT8Ds, which are decidedly NOT FADEC. “Just fire-walling it” will almost always exceed operating parameters and cause engine damage, if not failure.
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Nov 25, 2018 23:55
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MrYenko posted:Air Florida 90 was a 737-200 with JT8Ds, which are decidedly NOT FADEC. “Just fire-walling it” will almost always exceed operating parameters and cause engine damage, if not failure. Yeah thats why I said push it to temp/torque limits, whatever it is.
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Nov 26, 2018 01:26
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I’m glad someone at the company today had the intelligence to cancel our last two legs today instead of returning to Chicago: KORD 252339Z 2600/2706 04022G32KT 2SM -SNRA OVC008 TEMPO 2601/2603 1/2SM SN OVC006 FM260300 02025G35KT 1/4SM +SN BLSN(blowing snow) FZFG(freezing fog) VV004(vertical vis. 400ft) TEMPO 2603/2607 02030G40KT 0SM +TSSN FZFG(freezing fog) VV001(vertical vis. 100ft)CB FM261000 36023G35KT 1SM -SN BLSN(blowing snow) BR OVC008 FM261300 34018G28KT P6SM BKN009 OVC015 FM261800 31012G20KT P6SM BKN030 Thunder snow! 
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Nov 26, 2018 03:35
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Butt Reactor posted:I’m glad someone at the company today had the intelligence to cancel our last two legs today instead of returning to Chicago:  There's a TAF block for the Seattle area tomorrow morning that reads WS020/18050KT, which I had never seen before Who's ready to see how low groundspeed readouts can go at 2,000AGL
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Nov 26, 2018 04:58
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I love ThunderSnow because that poo poo is a get out of work free card every time. I’ve never mentioned it to anyone without them cancelling immediately. Thanks ThunderSnow!
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Nov 26, 2018 05:01
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a patagonian cavy posted:
I brought a PC12 in over the numbers at less than 50kt gs with 47kt right down the runway.
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Nov 26, 2018 05:24
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e.pilot posted:I brought a PC12 in over the numbers at less than 50kt gs with 47kt right down the runway. My flight school has 152s so I could probably hover without pushing it too hard
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Nov 26, 2018 05:37
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