T.T.B.
Greetings T.T.B.:
To the best of my knowledge the FAA still recommends the following: Do not retract the gear until the aircraft is positively airborne and insufficient runway remains for landing. There are two reasons for this. First, if the airplane doesn't have a positive rate of climb and the gear is retracted, it could settle back to the runway, which means you get to make new friends at the local FAA office. Second, if you delay retracting the gear and the engine quits on takeoff, you might still be able to land on some portion of the runway. The real issue here concerns your perception of the amount of runway required to become airborne and then come to a stop on the end of that runway after an engine failure (or for any other good reason). It might be a lot longer than you think.
In my Beech A36 Bonanza, at sea level on a standard day with no wind and at maximum gross weight, it takes approximately 1,500 feet of runway to clear a 50-foot obstacle on takeoff. To land over a 50-foot obstacle under the same conditions takes approximately 2,000 feet of runway. Thus, to climb to 50 feet, have an engine failure, and land to a complete stop requires at least 3,500 feet.
Well, it actually requires a little more runway than that. The distance I quoted to land over a 50-foot obstacle is based on a full-flap approach at a slower speed than that used for a normal departure. But we don't normally climb this slowly, nor do we use full flaps for takeoff. We won't always be able to extend the flaps fully for the unexpected landing, either. Furthermore, many pilots don't use the full length of the runway, nor do they maximize their performance on every takeoff. Thus, as a general rule, the actual distance to land will be longer.
Given these considerations and the fact that a skilled test pilot, flying a newly manufactured plane, determined the takeoff and landing distance shown on the performance chart (the average pilot would be challenged to obtain similar performance numbers), it's safe to say that the average pilot is looking at nearly 4,500 to 5,000 feet of runway to climb to 50 feet, then land to a full stop. Unless you're departing on a long runway (more than 5,000 feet, for instance), it's likely that you've used up all the available landing distance the moment you lifted off. This is why it's often more reasonable to raise the gear after liftoff, when a positive rate of climb is established.
What do you get in return if you raise the gear as soon as a positive rate of climb is established? The airplane climbs faster. This extra bit of altitude gives you more options if the engine quits. You might even elect to keep the gear up and belly in after an engine failure, given the airplane's increased glide performance. Personally, I'd rather have additional altitude to glide to a vacant field and land gear up than land gear down in less hospitable territory (i.e., where there are cars, telephone poles, telephone wires, big rocks, near an FAA office, etc.).
Ratings Race
Dear Rod:
I'm 19 years old and am just finishing my commercial single-engine rating. I want to become a CFI and eventually fly professionally. What is your opinion of starting work on the multiengine rating before I work on the CFI rating? I don't have much money, but I think that having the multi rating first would give me a better chance of getting hired by an airline. I'm even thinking of bypassing the regular CFI rating and going for the multiengine CFI rating first. What do you think about that?
Ross
Greetings Ross:
OK, you asked for my opinion, so here it is. I think both ideas are unwise. Unless you already have an opportunity to fly a multiengine airplane, you'll probably hinder your progress in the long run by obtaining that rating first. I suggest you obtain your CFI rating first, which will allow you to build flight time while making money. It's ultimately flight time that will get you hired. You'll also build confidence and knowledge. This is something you'll want to have when you eventually earn your multiengine CFI rating.
Regarding going for the multiengine CFI rating first, well, this can be done, but I don't think it's a wise idea. First of all, you want to build flight time. Multiengine students are a prize commodity among CFIs. They tend to get pounced upon by CFIs when entering the FBO, and as a new CFI you're likely to be at the bottom of the pecking order in terms of getting one of these plum assignments. You won't build much flight time that way. You'll want more experience under your belt teaching someone to use one engine before teaching them to use two, and potential multiengine students will expect someone with more experience.
Flap Over Slips
Dear Rod:
I have had two instructors teach me different things about slips with flaps extended. The first one said slips were the best way to lose as much altitude as fast as possible without increasing airspeed, and encouraged me to practice them. However, I was on final with the second instructor one day when I started slipping to correct a high final approach, and he just about took my head off, pointing out the placard mounted underneath the flap control that read, "Avoid slips with flaps extended." He said that it changed the aerodynamics dangerously, affecting the way air traveled over the rudder. Which one should I believe? I used to use slips all the time. Now I am not sure if it is safe.
Josiah
Greetings Josiah:
As far as I know, there are no general aviation airplanes that prohibit a slip with flaps extended. The Cessna 172 you mention says that slips should be avoided with flaps - and some aircraft, including newer Cessna 172s, say that slips should be avoided only with full flaps. It doesn't say that slips are prohibited. My friend Barry Schiff, in his book, The Proficient Pilot, Volume 1, talks about this issue. According to Barry, the side effect of slipping with flaps extended in this airplane is a slight vibration or oscillation of the elevator. This results from the blanketing of the rudder by the flaps in a slip. The only concern here is that the elevator vibration might unnerve the pilot. There is no indication that it produces a dangerous aerodynamic condition.
Rod Machado is a flight instructor, author, educator, and speaker. A pilot for 32 years and a CFI for 28, he has flown more than 8,000 hours and owns a Beech A36 Bonanza. Visit his Web site (www.rodmachado.com ).
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