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About Qavion2

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  • Birthday December 12

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    On a pedestal
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    Fixing stuff

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    Regarding the >FUEL TANK/ENG message. There is a 120 second timer applied to the message, so, in theory, the message should not appear until the inboard tanks are a few hundred kilos below the equal quantity point. For PMDG: refer to System Schematic Manual 28-41-02 Page 101 sheet 3. Perhaps the active pilots on the beta team can confirm this. i.e. the manuals agree with the real aircraft. This delay should take care of fuel sloshing around in the tanks affecting the fuel quantities and regenerating the X FEED CONFIG message, although there is also a 120 second timer on the X FEED CONFIG message in certain circumstances (logic also in the SSMs) Cheers JHW

    Kyle has a good point, but, if the team is not so busy... Someone on the Aerowinx forum said (about two years ago) that an FCOM had the following text: Chapter 15 Alerts inhibited during take-off EICAS advisory message TCAS OFF - inhibited on ground until 400ft RA. Alerts inhibited during landing EICAS advisory message TCAS OFF - inhibited from 400ft RA until go-around at 400ft RA. A British Airways 744 pilot responded and said that he didn't get a TCAS OFF message in his company sim. Another 744 pilot (Atlas) commented that he had never seen the message on the ground. I also found a mention of it in an old Boeing Service Letter (circa 1998): IDS software Update: >TCAS OFF (Level C) Revised logic to inhibit the message if radio altitude is less than 400 feet. It would be far easier for one of your real (current) pilots to check this than for me to look through hundreds of pages of Service notes. Also, if your pilot is from an independent airline, it would add a 5th reference. Note that I have manuals which say the TCAS OFF message does appear on the ground, but they are well out of date. I also have a really old photo showing the TCAS OFF message on the ground during Standby Power only. This may either be because the photo was really old (pre-service bulletin) or because the relevant radio altimeters were not powered. The comments on the Aerowinx forum were temporarily "muddied" because some of the manuals didn't specify if it was a takeoff inhibit or if the inhibit was in force at all times below 400feet. The big sim tests seemed to prove that it wasn't just a takeoff inhibit. The EICAS message >TCAS OFF is not to be confused with the one on the ND (which does appear on the ground).. Cheers JHW

    Regarding subjectivity: The perception of light intensity is always going to be an issue in a desktop simulator. When was the last time we were blinded by directly looking at an image of the sun on our desktop computers? I've been blinded by real taxi lights, too, but only by looking directly at them, not by looking at the effect they have on a dry tarmac when I'm a few plane lengths away (as shown in the poster's photo). If pure white on a monitor represents "blinding" light, then you would expect some intensity reduction for light on the tarmac. e.g. as in this YouTube clip of a Polar 744 taxying to the gate with the taxy lights on. Looking at the video, I would say that light intensity needs to be somewhere between v2 and v3. I did hear of one guy in our overhaul workshops who mounted forward facing 767 landing lights on top of his 4WD... but this was purely for offroad use. Probably for kangaroo spotting. Cheers JHW

    I recall that Atlas starts 1 & 4 at the same time, so it shouldn't cause any problems. Switching power sources from APU to engine should not cause power breaks. The two power sources are synchronised prior to switching... and for a very brief moment (less than 120 milliseconds), both APU and Eng power are put online at the same time (on the same side/half of the split system bus). It's known as a NBPT (no break power transfer). I believe the 744 was the first aircraft to have this system.
  5. Engine Start Problem

    I would still challenge the Tech notes' definition of "engine bleed air valves", Bertie. Just pushing the ENG BLEED switch will enable the PRSOV open solenoid. Pulling the start switch with the N2 below 50% will enable the PRSOV's reverse flow solenoid. It's then up to the EEC to open the start valve, turn on fuel, etc, if the Autostart switch is on. I have the PRSOV logic diagram, but it's not easy to read and probably copyrighted. I can't see any signal path from the EEC to the PRSOV (RR/GE). Cheers
  6. Engine Start Problem

    Bertie, I don't think this is correct. The EEC has no control over the PRSOV. My books say that the logic inside the ASCTU for the PRSOV "reverse flow" solenoid (which allows the APU bleed air to go backwards through the PRSOV) and the PRSOV "open" solenoid need to see the fire switch handle in and the ENG BLEED switch depressed. Start switch and N2 (or N3) speedcard signals are also required for the reverse flow solenoid. Nothing will flow through a PRSOV without the respective Eng Bleed switch being armed. Cheers JHW
  7. Oh s***

    Did you eventually get the artificial horizon to appear?
  8. FMC Maint pages

    Modelling the CMC would be 1000 times harder than modelling the stuff the pilots see. Even the Boeing Maintenance Manual just scratches the surface of the CMC. Perhaps if basic Confidence Tests were modelled, but even these would involve complex timing issues (displays showing changes for certain periods of time). Regarding tests: You would have to know the effects of losing power on certain parts of the system at certain times during the tests. What happens when you cancel tests at x seconds? Some folks might think think that cancelling a test immediately puts the aircraft back into the normal mode, but I've seen the CMC lock up for long periods while this happens. You would have to model things that aren't modelled at the moment. e.g. airconditioning valves being open certain percentages at certain times. Certain switches have to be in certain positions for the tests. You would have to know what happens to the testing system if the switches are not in those positions. For a desktop sim, the CMC developer would have to make simplifications, do workarounds, etc. Because of this, it would have no value to say, an aircraft avionics instructor (who is looking for fidelity). Even on million dollar big sims, avionics instructors have told me that certain tests don't work the same way as on the real aircraft. This stuff would be boring and meaningless to 99.99% of users. The novelty would disappear very quickly, even if you were an aircraft engineer.... Engineers have real aircraft to play with My two spanners worth...
  9. APU Freezing over?

    The 744 apu inlet door needs an "on ground" signal to open. I believe there is logic in the APU controller which inhibits APU start if the door is not open. It may be possible, however, to simulate an on-ground signal by pulling certain circuit breakers in flight. The aircraft electrical system has been modified to allow APU electrical power on to the busses if all engine generators are below operating speed, so if the APU can be started in the air, you may be able to get power on the busses (but it's not going to be much help if all the engines aren't powered up... You're still going down). Also, with those circuit breakers pulled, other systems will be behaving abnormally. The Classic 747 used to have the ability to start in the air, but this ability was removed on many airlines, probably due to safety reasons (fire hazard, etc). Twin jets traditionally have the ability to start the APU in the air (because they only had one generator per engine), but aircraft like the 777 have two generators per engine. The 744 APU is not really designed to be started in the air. Like most engines, they are difficult to fire up at high altitudes. Also, an APU which has been cold-soaked for long periods doesn't like starting. It has to thaw out first. Sometimes APUs can't even be started on the ground after long cold flights.
  10. Pilot aggression

    As a former avionics engineer, and having repaired many switches and buttons on Boeings, I certainly wouldn't encourage ham-fisted operators to maul the switches. I've seen frightening videos of pilots operating the spring loaded landing gear levers and heard the levers slamming back into the instrument panel. Whilst the levers themselves are built for a certain amount of abuse, the microswitches in those assemblies are probably a little more sensitive. Having said this, the tungsten filaments in the switchlamps tend to get pretty hot. Sometimes unbearably so. You don't want to leave your fingers on them for too long. If the pilots seem to jab at them quickly, perhaps this is one reason why they do so. Note that heat has a tendency to weaken the plastic parts in switches, so they do need to be treated with some care. Wear and tear takes a toll on switches, no matter how expensive they are. Price is not always a guarantee of rubustness. Aircraft parts will always come at a premium.
  11. Slow slats retraction

    Unfortunately, I have no information on what would happen if half the flap transmitters were working.
  12. Slow slats retraction

    No problems last time I checked. There is even an option to modify the flap logic for #1 & #4 ADP activation. Note that the logic is based on inboard TE flap transmitter position signals. If you can't get the inboard flaps to extend, this can create a few problems for other systems. However, since the inboard TE flaps are functioning normally, then we have to look elsewhere for a cause. Cheers JHW
  13. Slow slats retraction

    Ticket submitted?
  14. Slow slats retraction

    Don't forget that ADPs are triggered by both configuration and system low pressure. Depending on the aircraft, as soon as the flaps start moving or, in some cases, whenever the TE flaps are not zero, the ADPs cut in to keep up the pressure and, importantly, the flow. Pressure is not always a good indication of hydraulic power.
  15. What does this do?

    Did you mean Line-Replaceable? i.e. something which can be easily replaced (e.g. a rack mounted unit with simple lock in devices or similar).. as opposed to a flight control surface or landing gear assembly. Some airborne data loaders (ADLs) have a percentage load digital display, but it's like a typical PC time-to-download displays. The speed varies from moment to moment. You can never predict how long it will actually take. Cheers JHW