albar965 / littlenavmap

Little Navmap is a free flight planner, navigation tool, moving map, airport search and airport information system for Flight Simulator X, Microsoft Flight Simulator 2020, Prepar3D and X-Plane.

Home Page:https://albar965.github.io/littlenavmap.html

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Suggestion: Alternate method to collect cruise performance calculation

JT8D-17 opened this issue · comments

commented

As of version 3.0.5, the "cruise" phase of the performance calculation depends on the flight plan cruise altitude set in the flight plan.
If the aircraft is cruising, but not at the flight plan altitude, the performance phase will be treated as "climbing", thus incorrectly assigning collected fuel flow data.
Thus, the flight plan altitude has to be constantly adjusted to ensure correct performance data calculation.
This makes it fairly tedious to collect data for helicopters as these will vary their cruising altitude quite a bit depending on the situation (obstacles, terrain).

Suggestion: The cruise phase of a flight should be determined by variation in vertical speed. If the aircraft's vertical speed has been less than +/- 50 ft/min within the past three or five seconds, it is automatically assumed that the aircraft is cruising and therefore, cruise fuel flow will be collected.

This could be offered as an alternative mode to the default one based on flight plan altitude, maybe with and adjustable vertical speed treshold and time interval.

Has to be added as an option since this would not work in some cases. For example, a departure which has a below altitude restriction would be detected as cruise.

commented

But isn't flying a departure/arrival leg at a constant altitude technically cruising?

However, I'm perfectly fine with having it as an option. Thanks for considering it.

But isn't flying a departure/arrival leg at a constant altitude technically cruising?

What's collected when flying 20 NM at 4000 ft due to a below altitude restriction does not contribute anything useful to a cruise altitude at FL 380. 🙂

Here is a nice one. EIKY depart using SHA3A. Keeps you more than 40 NM below 4000 ft before you can climb to cruise after SHA:
grafik