What’s the difference between TERPS and OEI Runway Analysis?

TERPS (Terminal Instrument Procedures):

• Designed for all-engines-operating conditions.
• Used to develop SIDs, STARs, and instrument procedures.
• Often includes climb gradients for ATC, noise abatement, or navigation, not obstacle clearance with an engine failure.
• May ignore low, close-in obstacles if they would make the procedure unusable.

OEI Runway Analysis (APG):

• Based on AFM-certified performance with one-engine inoperative.
• Ensures regulatory obstacle clearance (i.e., 35 ft vertically, 200–300 ft laterally).
• Uses a defined corridor per AC 120-91 to evaluate obstacles.
• Required for Part 121 and 135 operators.