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5

Altitude Intervention will start a descent only if VNAV is the active mode (and the MCP altitude is below the current cruise altitude). If you're in Altitude Hold, then VNAV isn't active, and the Altitude Intervention button won't start a descent. On the other hand, Level Change is its own mode, and selecting it (with a different altitude set in the MCP than ...


4

With both restrictions entered on the LEGS page, VNAV will build a deceleration segment immediately prior to the point to reduce speed from 240 to 210 knots in (almost) level flight. There is no need, typically, to come out of VNAV, use the speed brakes, or do anything else like that in order to have VNAV meet both speed & altitude constraints. Thus, the ...


3

As a generic (non-737 specific) answer, it means that when the Flight Director is armed to capture an ILS glideslope, the VNAV flight director mode, being a vertical path based on baro altitude, is cancelled once the aircraft passes through a waypoint that the RNAV system calculates to be the geographical intercept point of the ILS glideslope beam (the ...


2

The lateral NPS will be present if there is a defined LNAV track active, and the APPROACH mode (i.e. to track an ILS) is not active. The vertical NPS is inhibited until the FMC-computed Top-Of-Descent point, so it won't be present during an intermediate level-off during an RNAV departure. It's also inhibited after GS Capture, since the ILS glideslope is then ...


2

So your CRZ page shows your cruise altitude as FL 410, but you've leveled off at FL370, which is what's in your MCP Altitude window. Now ATC clears you to climb to 410. You set 41,000' into the MCP Altitude window. At this point, your FMA vertical mode changes from VNAV to Altitude Hold. The light in the Alt Hold button is on, and the light in the VNAV ...


1

The answer above is largely a complete one. I would only adf a couple of small details. FMC computations determining where to set the path are more accurate if winds aloft are entered for multiple levels on the descent forecast page. As to speeding up or slowing down to manage energy, you would need to consider the descent airspeed in relation to where the ...


1

Yes, a VNAV PTH certainly needs descent winds so as to calculate and construct the most efficient flyable PATH. The PATH as we know. is built backwards from the landing RWY threshold to Top Of Descent (TOD). Before I continue, I must say that sometimes managing VNAV PTH can become an unnecessarily complex task, if that's where you're coming from. We always ...


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