Some flying schools and charter operations still persist with the illusion that light twins can have an engine failure and continue. Maybe yes; maybe no: either way you and your passengers have just become test pilots and observers.
The current 14 CFR Part 23 single-engine climb performance requirements for reciprocating-engine twins are as follows:
• More than 6,000 pounds maximum certificated takeoff weight and/or Vso of more than 61 knots. The single-engine rate of climb in feet per minute at 5,000 mean sea level (MSL) must be equal to at least .027 Vso squared. For twins type-certificated on February 4, 1991, or thereafter, the single-engine climb requirement is expressed in terms of a climb gradient, 1.5 percent.
• 6,000 pounds or less maximum certificated takeoff weight and Vso of 61 knots or less. The single-en- gine rate of climb or climb gradient at 5,000 MSL must simply be determined. The rate of climb could be a negative number. There is no requirement for a positive single-engine rate of climb at 5,000 feet or any other altitude.
Regarding climb performance, the light twin with OEI will perform marginally at best and may not be capable of climbing at all under existing conditions. There is no requirement that a light twin in the takeoff or landing configuration must be able to maintain altitude, even at sea level, with OEI.
And my personal favourite from the FAA!
Landing Gear Selected Up, OEI Climb Performance Inadequate
When operating near or above the single-engine ceiling and an engine failure is experienced shortly after lift-off, a landing must be accomplished on essentially whatever lies ahead. The greatest hazard in an OEI takeoff is attempting to fly when it is not within the performance capability of the airplane to do so.
A recent study revealed a very high success rate for off-airport engine-inoperative landings when the airplane was landed under control. The same study also revealed a very high fatality rate in stall-spin accidents when the pilot attempted flight beyond the performance capability of the airplane.