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Originally Posted by shaneslv
Been following this thread for quite a while and i must say WOXOF you are living my dream
You mentioned earlyer that you have flown into shannon airport in ireland (EINN). Do you fly this route often? I ask because i live about 5 mins from the airport.
No, not too often. I think I've been to Shannon two times in the last year. One thing that's nice about the flights to Ireland is that everyone (crew and passengers) clears U.S. customs before taking off from Ireland on our trip home. This is unique to Ireland out of all international destinations and I'm not sure why this is the case.
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Also i understand that when departing a airport pilots use SID's (Standard Instrument Departure) which tell the pilot the route to take when departing an airport by providing waypoints and what altitude to be at at each waypoint. Are these SID's saved on the FMC and the pilot simply selects the relevant SID and inserts it into the flight plan ? Or will the pilot enter the waypoints manually ? Are the SID'S for every airport saved on the FMC ?
Yes, all the SIDS are stored in the database on the FMC so we simply select the appropriate departure. The waypoints, along with altitude and speed restrictions, are automatically loaded.
The database is updated every 28 days and I check it for currency before doing any other initialization of the FMC. Two databases are stored on the FMC, with one selected as active. The other database will be the future database.
Here's a sample I cut out of a training document:
The active database shown on this screen expires at 0900Z on July 23, 1999. If I get on the plane and see that the active database has expired, then I select the secondary database and make it primary (an operation that requires two button pushes). At some point over the next few weeks, Maintenance will load in the next database cycle so that it will be there when it's needed.
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If the autopilot is switched on after takeoff will the aircraft fly the SID automatically? Will the aircraft climb at a rate which will satisfy the SID? ie if the SID speculates to be at 3000ft at point A and 5000ft at point B will the aircraft modify its climb rate to pass Point A at 3000ft and B at 5000 ft
It will if we have LNAV and VNAV selected. The Flight Director (which is what drives the autopilot) requires a vertical mode and a lateral mode. A simple example would be to select HDG for the lateral mode, which will cause the FD to track whatever heading we've selected, and Flight Level Change (FLCH) for the vertical mode, which will cause the FD to command a climb or descent to the selected altitude.
When we select LNAV, the FD will track the entire route loaded into the FMC. VNAV will do the same for altitude and speed restrictions, except that it won't exceed the altitude we've selected in the Altitude window on the Mode Control Panel (MCP). That's not usually an issue for a SID because the initial climb clearance is usually to an altitude at or above that for the fixes on the SID.
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You say sometimes you like to hand fly on takeoff. Is it a challenge to hand fly the SID? Will the flight director display the attitude required to fly the SID? And you simply follow the director?
No, it's not that challenging...I just follow the Flight Director. The one thing that will get you is a large heading change at a fix. If you wait for the FD to tell you when to bank, you'll overshoot the path by as much as 0.4 miles. So you have to recognize that the turn is coming and initiate the turn early.
For a big heading change, I'll start the turn using a distance from the fix equal to about 1% of my groundspeed (a little less if the heading change isn't that big). I can monitor my path by looking at the magenta line on my Nav Display and I can watch my deviation from the path by having the Progress Page up on my FMC display.
At some airports in Europe, there's a big emphasis on being
precisely on the departure path and some hefty fines for the company for any deviations. In these cases, it's not a bad idea to just let the autopilot do the job. If I hand-fly it, no one's going to give me a pat on the back for being right on course, but I'll have a lot of explaining to do if I incur a fine. If the plane incurs a deviation while the autopilot is engaged, I'm blameless since I've followed company procedure.
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Is the procedure the same for the STAR ?
Yes, except that the plane won't start any descent, even if the STAR (Standard Terminal Arrival Route) calls for it, until we've selected a lower altitude in the Altitude window on the MCP. There's a good reason for this. Although we expect a STAR and know what it is from our original clearance, we can't change altitudes until we're cleared to do so.
If we're getting close to the point where we need to start down to comply with the planned arrival route, we'll just let ATC that we're "looking for lower." Occasionally, ATC puts us in a box by keeping us high too long and then clearing us to descend and still expecting us to comply with the STAR. Although we can increase our descent rate pretty dramatically and still make most crossing restrictions, it can be impossible to do if there's also a speed reduction associated with the fix. The 757, much more than the 767, does not like to come down and slow down at the same time. It's a slick airplane and the pilot has to stay ahead of it to manage the descents. In these cases, we sometimes have to tell the controller that we can make the altitude or the speed, but not both. We leave it to the controller to decide which is the more critical parameter.
That reminds me of an old story I've heard about a 727 crew being cleared by ATC to descend to cross a fix at a certain altitude. The controller had been late with the clearance and it would require a big descent rate to comply. The Captain told the FO to tell the controller that they'd be unable to make that restriction. But the FO knew that the 727 was perfectly capable of making the restriction and told the Captain "We can make that easily if we use the spoilers." The Captain replied, "Those spoilers are for
my mistakes, not his."