Constant Angle Non-Precision Approaches (CANPA):

CANPA involves a stabilized constant angle descent from the Final Approach Fix (FAF) to the runway, rather than descending quickly to the Minimum Descent Altitude (MDA) and leveling off. This technique enhances safety and reduces crew workload by providing a stable flight path and simplifying final approach tasks.

Key Elements of CANPA:

1. Computed Landing Altitude:
   • Reference landing altitude is 50 feet over the runway threshold (TDZE + 50′).
2. Computed Touchdown Position:
   • This is used as a zero-distance reference. Altitude checks at various distances from the runway should be calculated if not available on the approach chart.
3. Computed Descent Rate:
   • A constant descent rate is flown to the Derived Decision Altitude (DDA) or Derived Decision Height (DDH).
   • Descent rate corrections of no more than ±300 fpm are allowed. If corrections exceed this threshold, the approach is considered unstabilized and requires a go-around (except for momentary corrections).
4. Missed Approach:
   • At the DDA (H), if required visual references are not established, an immediate missed approach must be initiated. The aircraft should climb on track to the Missed Approach Point (MAP) and follow the published missed approach procedure.

Carrying Out a CANPA Approach Without a Published FAF:

If the FAF is not published, a pseudo FAF can be determined.

1. Calculation of Pseudo FAF Crossing Height:
   • Identify the inbound track and use the initial or intermediate approach altitude to define the pseudo FAF location.
2. Descent Rate Computation:
   • Compute a descent rate based on a 3-degree glide path from the pseudo FAF to the runway.
3. Distance Determination:
   • Use aids such as DME, FMS, GPS, or ATC Radar to determine the distance of the pseudo FAF and the aircraft’s position relative to touchdown.
4. Conducting the Approach:
   • Perform a straight-in approach using the computed descent rate and established pseudo FAF parameters to ensure a stabilized descent path to the runway.