https://library.wmo.int/doc_num.php?explnum_id=7359

The system shall aircraft phase to ground phase when all of the following conditions are satisfied:

1. CAS is equal to or less than 100 knots or CAS data is invalid

2. Air/ground switch indicates ground or weight on wheels is true

The system shall aircraft phase to ascent phase when all of the following conditions are satisfied:

1. Computed Airspeed CAS > 100 kn

2. Altitude Rate > +200 feet/min

3. any of the following conditions are satisfied:

• Pressure based scheme: Pressure Altitude <= Top of Climb

• Time based scheme: Flight time since take‐off <= Ascent Total Duration

TOP OF CLIMB (X100FT)

DEFAULT = 200, RANGE = 150‐350

ASCENT TOTAL DURATION (SECONDSX10)

TIME BASED SCHEME DEFAULT = 051, RANGE = 051‐111

The system shall aircraft phase to en‐route phase when all of the following conditions are satisfied:

1. Computed Airspeed > 100 kn

2. any of the following conditions are satisfied:

a. Pressure based scheme: Pressure Altitude > Top of Climb

b. Time based scheme: Flight time since take‐off > Ascent total duration

TOP OF CLIMB (X100FT)

DEFAULT = 200 RANGE = 150‐350

ASCENT TOTAL DURATION (SECONDSX10)

TIME BASED SCHEME DEFAULT = 051 RANGE = 051‐111

The system shall aircraft phase to descent phase when all of the following conditions are satisfied:

1. Computed Airspeed > 100 kn

2. Altitude Rate < ‐200 feet/min

3. Pressure Altitude < Top of Descent

TOP OF DESCENT (X100FT)

DEFAULT = 200 RANGE = 150‐350

a. Dynamic pressure ( q, lb/ft2 ) 14.8 < q < 375

b. Angle of attack (α, deg) -4.0 < α < 20

c. Mach number (M) 0.1 < M < 3.5

d. True Airspeed (TAS, ft/s) 112 < TAS < 3436

e. Equivalent Airspeed (EAS, ft/s) 112 < EAS < 562

f. Computed Airspeed (CAS, ft/s) 100 < CAS < 500 ==> 59.2484 < CAS < 296.242 knots

g. Corrected pressure altitude (HPC, ft) 0 < HPC < 105,000

1 ft/sec ==> 0.592484 knots

100 ft/sec ==>