I've been doing a lot of check rides in multi engine and complex airplanes lately. I've noticed a change in fundamentals of when to raise the landing gear. I thought I'd share my thoughts on the subject.
It seems that the "new" idea of raising the gear is to wait until "out of usable runway". When I ask why they do this the response has universally been "if I lose an engine or need to abort I can put it back on the runway". I like to challenge some of the ideas that pop up out there to see if they make sense, so here are a few of questions I like to ask.
1. Have you ever been tried or been trained to abort a takeoff shortly after lift off? 90% have said no.
2. If you did abort a takeoff from low altitude, how much forward distance would you use? Will you be able to land and stop on the remaining runway? Think about what you have to do here: 1, recognize a problem, 2, make the decision to abort, 3, lower the nose and reduce the power, 4, lower flaps. 5. Think about airspeed (will it be high, low or just right), 6, Think about sink rate (what will it be). 7, Flare. 8, Brake to a stop.
3. What are the pros and cons to leaving the gear down until "out of usable runway". Pros-If I do have to abort I can land on the gear and prevent damage (provided you're still on the runway). Cons- Increased drag which will reduced reduce the rate of climb 250-300 feet per minute and decrease acceleration or, if the engine quit, rapidly reduce airspeed until the nose is lowered sufficiently.
Back in the so-call "old days" we where taught to raise the gear with a positive rate of climb. Your rate of climb was better, acceleration was increased and If an engine did quit, the airspeed wouldn't bleed off as quickly. I think most would argue having more altitude gives you more options. When you're low to the ground even having an extra 200 feet of altitude will increase your landing areas.
The biggest problem I see with waiting until "out of usable runway" is that the pilot waits too long to raise the gear that there is no way that they will be able to land on the remaining runway. To me I would rather have the additional altitude and less drag hanging out there. If the engine does quit, the insurance company owns the airplane. I can focus on flying the airplane as far into the crash as I can.
Just my 2 cents and I could be wrong!