How are close-in obstacles handled in climb performance analysis?

Under TERPS/PANS-OPS standards, low, close-in obstacles may be excluded from consideration if including them would result in an extreme required climb gradient. When this occurs, the obstacles will be clearly noted as excluded in the SID (Standard Instrument Departure) description.

To determine whether these obstacles can still be cleared, a Runway Analysis (RWA) must be performed. This analysis assumes:

• An engine failure is recognized at or after V1, and
• The takeoff is continued with one-engine inoperative (OEI).

The RWA then calculates the maximum takeoff weight at which obstacle clearance can be achieved under OEI conditions.

If no engine failure occurs, the aircraft will:

• Use less runway, and
• Achieve a higher climb gradient with All Engines Operating (AEO).

Therefore, the maximum weight determined by RWA will, by definition, clear the close-in obstacles when operating under AEO conditions.