Minimum subsonic distance

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Minimum subsonic distance

Departure :

In previous versions of CPS, it was possible to perform flight without subsonic step.
This means that the aircraft was considered to go into supersonic immediately after takeoff.
It was obviously not realistic.
CPS-NG has a draft of a new feature: Minimum Subsonic Distance.

Indeed during the departure, Concorde must first climb to 10000ft/FL100 at 250 or 280 kt depending on the case. In addition, an anti-noise procedure penalizes the initial climb.
Then, climbing to subsonic cruise level (usually FL260/270 at MTOW) is not a snap.
Initially, a fixed minimum subsonic departure distance of 54 NM is taken into account even if no subsonic level is planned.
It corresponds to an anti-noise procedure then a climb to FL100 at 250kt at MTOW, ΔISA 0 i.e. 15°C and no wind, then a climb to FL260 at VMO/M.95 still at MTOW and no wind.
Later, a function will calculate this distance more precisely.
The maximum subsonic distance, corresponds to the total ground distance of the flight / 3.
For an EGLL-KJFK flight of 3160NM, a subsonic level should therefore be between 54 and 1053NM.
A message will warn the user if these distances are not respected.


Arrival :
The fixed minimum subsonic arrival distance corresponds to the distance traveled from passing below M1.0 at FL 385, a descent at 325kt down to 1500 ft. np wind, at ΔISA 0, it is 91NM.
As for the departure, the maximum subsonic distance will be equal to the ground distance of the flight / 3
For an EGLL-KJFK flight, 3160NM, a subsonic level should therefore be between 91NM and 1053NM.
A message will warn the user if these distances are not respected.
I think that this way, the fuel calculation will be more realistic.
Do not hesitate to send me your suggestions.