Activating variable after running the subroutine

[simurq]

The main subroutine returns lots of stuff unrelated to aircraft (eg., weather forecast, distances and headings between waypoints, etc.). Inside of this subroutine I have a set of functions to calculate various aircraft parameters such as true airspeed, fuel consumption, etc. which use a few static variables called from GetParams() which returns an array of values depending on type of aircraft pre-selected by the user from a drop-down list before running the main subroutine. Eg.:

Public Function GPH(PP As Integer, plane As Integer) As Double
'* Calculates cruise fuel consumption (gallons per hour)
'* Input: (i) "PP" as engine brake-power percentage; (ii) "plane" as type of aircraft

    Dim AircraftData As Variant
    
    AircraftData = GetParams(plane)
    
    GPH = AircraftData(9) * PP ^ 2 + AircraftData(10) * PP + AircraftData(11)
    
End Function

Public Function GetParams(p_val As Integer) As Variant
'* Array contains static aircraft-specific data with the following parameters in order of declaration:
    '
    '   Type of aircraft
    '   Max TOW (lbs)
    '   Ceiling (ft)
    '   Wing area (sq ft)
    '   Rated engine power (hp)
    '   Climb fuel variables (for function CFUEL) - 4 items
    '   Cruise fuel variables (for function GPH) - 3 items
    '   CoeffClimb (CL) variables (for function KTAS) - 4 items
    '   CoeffClimb derivative (CL)' variables (for function KTAS) - 4 items
    '   Startup and taxi fuel
    
    Select Case p_val
        Case 1
            GetParams = Array("Cessna 172R Skyhawk", _
                            2450, _
                            12000, _
                            174, _
                            160, _
                            0.000000000003, -0.00000003, 0.00042, -0.0201, _
                            0.0002, 0.0901, 0.8544, _
                            0, 0.1257, -0.0333, 0.0454, _
                            0, 0.06285, 0.01665, -0.0681, _
                            1.1)
        Case 2
            GetParams = Array("Cessna 182T Skylane", _
                            3100, _
                            18000, _
                            174, _
                            230, _
                            0, 0.00000001, 0.0003, 0.1, _
                            0.0007, 0.0564, 4.796, _
                            -0.2215, 0.3476, -0.1113, 0.049, _
                            -0.33225, 0.1738, 0.05565, -0.0735, _
                            1.1)
    End Select


End Function

Now I want to give user a choice to select different type of aircraft from the same drop-down list to update say GPH() values without re-running the whole subroutine, i.e. only to update selected functions concerning aircraft parameters only after running the main sub.

How can I do that?! Namely, how can I activate the "plane" variable without running the main sub when I select a different type of aircraft from the menu?

Thank you!

Rustam