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About Qavion2

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  • Birthday December 12

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  1. My 2 cents' worth: In the real world, you would almost never start turning a 747 straight away. You would normally clear most of the parking area before turning. This way, there would be less chance of colliding with aerobridges, mobile steps, aircraft on the next gate, light poles and lines of parked cargo equipment. Taxiways also provide a wider space for the turn. To get a sharp turn in a small amount of space, initially you may reach the nose gear turn angle limit for towing (65 degrees). Also, the larger the steering angle, the more strain there will be on the main gear. More than 20 degrees of nose gear angle forces the body gear steering to activate. This helps alleviate the twisting forces on the main gear during sharp turns. Anyway, it's not something I would recommend for a beginner tug driver. Pushing an aircraft is a little like reverse parking a very long trailer/caravan
  2. Indeed. The Main and APU Battery Bus RCCBs have corresponding CBs on circuit breaker panel P6 in the cockpit. However, I don't know what the general policy is for resetting a circuit breaker of this magnitude. It guess it would be similar to resetting a GCB, but.. I don't know for sure. You can force the battery busses to use battery (or battery charger?) power using the Standby Power switch, but if there is indeed a short on one or more battery busses, you may do more harm than good. There are also RCCBs on the battery side of the battery busses, but if they didn't trip or didn't trip fast enough, you might affect the Hot Battery Busses, too. Some of those fire loop messages are a little worrying. I thought the APU Bat Bus provided power for the B loops. I can't easily think of a scenario where both the APU and Main Bat busses would be affected. Only the PMDG team would know what this scenario involves. Not sure. This comes back to whether or not the flap system can detect a DC power loss prior to flaps being used. Flap position data loss will be detected prior to flap use. Flap position transmitters use voltages from the FCEs. However, these voltages are derived from the overhead panel AC CBs. The FCE's do send (FCE status) data to user systems, but the text in the manuals is a little ambiguous regarding how (and when) that data is used. Unfortunately, without an airplane to experiment on, we probably will never know. I did pull FCE CBs a few years ago (for the purposes of sim development), but the CB combinations I used didn't give a full picture of their effect. Some combinations gave some pretty weird effects (such as the pitch limit indicators appearing on the PFDs with the flaps up). Cheers
  3. Complicated. e.g. STALL WARN SYS R, L This must be due to a sensor power failure rather than due to power to the stick shaker motors or MAWEA.The stick shaker motors are powered by the Main Battery Bus, but the aircraft would not know that the stick shaker motors were unpowered. There is no feedback from the motors. FLAPS PRIMARY I see some components of the flap system are powered by the main battery bus, but (in some cases) messages wouldn't be generated until you actually tried to move the flaps. There was a debate on another forum regarding what would happen if you lost DC power to the Flight Control Power Supply Units (FCE's). If you removed DC power (only), are you affecting the user systems or just the FCEs? I assume your problem is some kind of short on the battery busses. If there was a lot of current being drawn, the Remote Control Circuit Breaker/s (RCCBs) feeding the battery busses might have tripped (opened) before the short had time to drag down DC Bus 3 and the other DC busses. You would normally expect a power-related message if a TRU couldn't produce enough volts because of a short, but if the RCCBs acted before the current and voltage abnormalites were detected by the Generator Control Units, you wouldn't get a #3 TRU message and the #3 DCIR wouldn't trip. AFAIK, there are no voltage sensors on the Bat Busses themselves. If you looked at the battery indications, however, you might see that they were using very little current if the Remote Control Circuit Breaker/s for the Bat Busses busses had tripped and the battery relays were in their normal positions. In the case where the RCCBs had tripped, the batteries(or battery chargers in TRU mode) would not be commanded to take over from #3 Main DC Bus. This stuff is a lot easier to understand if you have a detailed schematic )))
  4. Generally, as long as the hydraulic fluid is being cooled with the heat exchangers in the wing fuel tanks, there shouldn't be a problem. There are time limitations on pump operation when fuel level is low on the ground.Last time I checked, it was 15 minutes. In the air, there is air cooling.
  5. Cargo fire suppression is another issue on these long haulers. Some of the aircraft's fire bottles give an instant blast, but then other bottles feed a slower supply for a certain amount of time. After this, nothing... If the fire restarts or if you have a fire in another cargo area, you're in trouble.
  6. I don't know how relevant this is, but the (real) 744 Approach Reference page allows a greater gross weight than your total, Angelo. A few years ago, on real 744s, I recorded the following values: Standard freighter (CF6) and pax (RR): 154.2 ~ 408.2 Tonnes Airspeed range: (Flaps 25) 120kts to 199 kts (Flaps 30) 115kts to 191 kts 747-400ER pax (CF6) 154.2 ~ 435.5 Tonnes Airspeed range: (Flaps 25) 120kts to 206 kts (Flaps 30) 115kts to 197kts
  7. I believe McMurdo Station in the Antarctica has an ice runway capable of supporting 747-400's, but I don't know if that's put into the calcs.
  8. Disregard... I misread Rudy's post 😚
  9. Qavion2

    Packs High Flow Simulation

    It's a bumpy cruise... His range-to-altitude arc (aka "green banana") has appeared...
  10. Qavion2

    Packs High Flow Simulation

    Looks ok now. Note that NORM is not supposed to be displayed. What's that weird blue tint on your Standby Instruments and Autobrake Selector?
  11. Qavion2

    Packs High Flow Simulation

    Should be faster than that. The packs should go into normal flow in "Cruise Clamp". This is defined by: Above 25,000' and within 100 feet of cruise altitude. The ECS miscellaneous card receives the climb, cruise, descent and altitude information from the EIUs. This data is passed on to the pack controllers and other controllers. Not all packs should go into normal flow at the same time. There should be a 15 second delay between packs.
  12. Here's a 747-400 display after a 4 hour flight... Note that the display (from the FMC) heavily favours the GPS position ">-O-<" and nav radio updating, not the IRU "weighted average". If one IRU wanders too far off, it will be ignored, and not used as part of the weighted average.
  13. Qavion2

    Glideslope callout on take off

    Strange. That was my understanding of how it worked. The official nav databases have an ILS-DME offset value and they have been incorporated in at least one high end desktop sim. If anyone is going to notice this, it's light aircraft pilots. Do you normally get 0.0nm at the glideslope transmitter? (allowing for the distance from the runway to the ground antenna).
  14. Qavion2

    Glideslope callout on take off

    Since they are forward of the main landing gear, it's probably best to have your gear up to prevent interference. I'm wondering if the original poster still had his langing gear lever down when he got the glideslope alert? As far as I can see, there should be no alert with the gear lever up (or off). The DME component of the glideslope ground transmitter is probably omnidirectional (as well as the receiving antennae). Caution must be used when using ILS-DME. DME transmissions contain an electronic offset to compensate for different ground antenna locations (with respect to the runway threshold). i.e. the transmitter may alter the response time delay to compensate for the antenna location. Depending on the relative position of the aircraft in relation to the antenna, you may get a substantial distance error.
  15. Qavion2

    Glideslope callout on take off

    My books specify a front course. This surely means the GPWS is just as smart as the PFD displays. The GS needle won't show on the PFD for intercept angles greater than 90 degrees to the front course. The indications will probably be so erratic after passing the transmitter (relying on reflections from ground objects), it wouldn't generate a warning. How many cockpit landings can you find on YouTube where the G/S pointer remains in view past, say, the mid point of the runway? Engineering 747-400 manual quote: Mode 5 is armed when the airplane descends below 1000 feet RA, the landing gear is down and the localizer is captured (within 2 dots) before descending below 500 ft. To rearm mode 5, the airplane must either descend below 30 ft RA or ascend above 1000 ft RA. Heading Compare The backcourse compare circuit inhibits mode 5 annunciations during backcourse. The airplane is in backcourse when the angle between selected runway heading and magnetic track is greater than 90 degrees.