Definition
The unadjusted climb path an airplane is expected to fly after takeoff with one engine inoperative, calculated using the manufacturer's certified performance data without any safety margin reduction. It represents the demonstrated performance of the aircraft, not the performance assumed for obstacle clearance planning.
Plain English
The climb path the airplane should actually achieve after losing an engine on takeoff, based directly on the performance numbers in the flight manual, with nothing subtracted for safety.
Context Anchor
Seen in instrument departure and takeoff obstacle-clearance planning, especially when checking whether an aircraft can safely continue a takeoff after losing one engine.
Derivation
Gross' here comes from the Old French 'gros,' meaning 'large' or 'whole.' In performance terms it means the full, unreduced figure — before any safety margin is taken off. This contrasts with the 'net' flight path, which is the gross path reduced by a required margin.
Why Pilots Care
It shows whether the airplane meets obstacle clearance requirements after an engine failure, directly affecting runway selection and takeoff weight limits.
Analogy
Think of gross pay on a paycheck: it is the amount before anything is taken out. The gross OEI flight path is the climb performance before the required safety deduction is taken out.
Grounding Statement
Picture the aircraft just after takeoff with one engine failed: the gross OEI flight path is the climb it should be able to make before adding the planning safety cushion.
Intuition Check
Gross does not mean sloppy or unusually large here. It means the full performance value before required reductions are applied.
Example Sentence 1
The performance charts gave us the gross OEI flight path, but for obstacle clearance we had to use the net path with the required reduction applied.
Example Sentence 2
During preflight planning the crew verified the gross OEI flight path against terrain data before accepting the takeoff weight.