The recent discussion on flap settings on takeoffs triggered this post.
In these types of discussions, sooner or later, someone will come up with “it’s in the POH, so this is how it must be done”, or even just “RTFM!”.
The question is: should we really blindly follow that little book like parrots? I think that is putting too much importance into something that has been written sometimes 40 years ago, in times when new aircraft models were “introduced” almost daily ( = without a lot of research)
Some thoughts:
- I think that POHs are usually rather good and accurate as far as the numbers are concerned. If Vy is 77 knots then it probably is 77 knots. POHs are much less good in the “procedures” / checklist department. Nothing beats 40 years of experience on a particular aircraft type and I think that there is a lot of nonsense in these POHs, making it worthwhile to deviate from it.
- Obvioulsly, primary students should initially be taught to stick what’s in the book, because they need more precise and clear guidance than experienced aviators.
- Some things in POHs are quite obviously just CYA driven, and of little practical relevance.
- An example (returning to the flaps debate): Piper Arrows (even more so Turbo Arrows) are nose heavy. Flapless takeoffs at foreard CG can indeed sometimes be a bit awkward. On the other hand, taking off with 25 degrees of flaps will usually frighten the passengers, since the moment you raise the gear, you will get the gear alarm. So, for these reasons I do occasially use 10 degrees of flaps on departures from longish runways, even though it’s “not in the book”. And invariably, someone (usually with little experience) will shout “that’s not the correct procedure!”
- When we are talking among “pro” pilots, I think we ought to go a little more “differentiated” about manufacturer procedures than just say “RTFM”, especially if these are dating back several decades.
Views?
I was not talking about T-tail Arrows … which are completely different animals.
Is 1000 hours in the Warrior enough experience to have an opinion? :-)
An example (returning to the flaps debate): Piper Arrows (even more so Turbo Arrows) are nose heavy. Flapless takeoffs at foreard CG can indeed sometimes be a bit awkward.
What are you getting at by “Awkward”? I’m sure you are talking about something real, but I don’t recognise it from my time with an Arrow II. I’m curious what you are refering to.
(I bet you don’t have another experience :-))
It’s probably more prominent on T-tails (haven’t flown a conventional tail Arrow for some time). The front wheel really sticks to the runway a bit. And one has to pull quite a bit. Then, when a certain speed is reached, the aircraft “leaps” into the air. Of course, one can finesse this a bit and make it less noticable, but it’s hard to get it perfect in the T-tail. I am always interested in the maximum comfort of my (apprehensive) passengers and the moment of liftoff (ideally without the passenger really noticing) is of utmost importance for the passenger experience. One notch of flaps really helps with that.
As a side note, the Arrow I fly (even though it’s non-turbo) is quite nose-heavy. With two POB in the front and nothing in the back, it is totally at the front limit of the envelope).
But I really didn’t want to open another PA28 / flaps thread, but rather a more general discussion of POHs. 
I need a week of weight training before each takeoff in the T-tail Arrow with trim neutral. Either that or try to trim away some of the weight before starting the take off roll – but then not too much or it will be a struggle getting the nose down. For the rest I have found the POH to be OK – but then I am fairly new to the aircraft with only about 30hours.
…the T-tail arrow takes an almighty heave at slow speeds, and at some point the elevator gets more bite and the nose goes up faster than intended. Probably because the stabilator is not in the prop slipstream. And with two up, it is likely right at the front of the envelope, making it harder. Didn’t find it difficult, but noticeable enough to make a point of it when transitioning a student from a Warrior to a T-tail Arrow… but never noticed anything in the “normal” arrows..
[break, break]
The previous name for a pilot operating handbook is “Pilot Information Manual”, and that is how I see it, with some information being extremely relevant (such as limitations, mass and balance), most of it quite important, and on occasion a bit of rubbish. I never ignore it, but sometimes choose not to use it / do things differently, entirely at my own peril.
I cook my own checklists (around flow patterns) but reconcile them with the POH, including understanding the implications of any changes.I sketch out the electrical system properly, especially for aircraft with a hard-to-fathom, suboptimal designed one (SR22 before SR22T, don’t know about the later models), and MY sketch goes into the checklist.
If it comes to the recommended techniques – there are so many ways to approach and land, basically if I want the performance in the book I fly by the book. But I know how I can get better landing performance than in the book (easy for landing distance, not so easy for landing roll and normally impossible for take-off). And in any case, I try it on a longer runway before doing it for real.
And there are many things not in the POH that are perfectly safe and fine. Glide approaches, side-slips, steep approaches, etc. are not all in there for all aircraft.
By the way – flying schools can be pretty bad offenders if it comes to ignoring the POH – here is a fun example.
I did my instructor rating on a PA28, and after getting it, asked the CFI what speeds to teach on the C152. It was 65kt. For lift-off, climb, and final approach. I knew that was a bit fast, but out I went and practiced a bit (hadn’t flown the thing for 20 years except for the spinning, and fancied that If I was going to teach, I should perhaps know what I am teaching), and my landings were absolute rubbish. Frustrated, I went back in, grabbed the POH, noted down the numbers, and went back out there. The next two landings were perfect.
And then I learned where the saying of balls and colour charts came from. And taught poor students how to land off an approaches that are over 10 kt too fast…
In a standard POH, section 2 details limitations. For N registry aircraft, this along with placards and Supplemental AFM section 2 is binding by regulation. The rest of the POH is not binding and is often dated and procedures are at best is a recommendation from the manufacturer.
In general the manuals are right on most procedures, I would say. What I like much less than flying by the POH are CFIs who try to reinvent the wheel. Not to mention that many CFIs take of in PA-28s with flaps, because they simply have not read the manual ;-)
The POH leaves enough freedom to develop your own style of flying. Also sometimes the numbers are wrong. For example the Best Glide speed for the SR22 for MTOM seems to be too low (100 KIAS works better). Also sometimes the POH is very conservative with T.O. and landing numbers. With both the Warrior and the SR22 I beat the POH on every takeoff and most landings.
Cobalt,
agree on all points.
So, it seems that we have been carried away a bit with that “you have to fly according to the POH because it’s the POH”, at least as far as procedures are concerned.
Of course, someone could always say “if you break something…, someone will point out to you that you were in violation of the POH”. And sure there will be someone who will.
The question is: are we going to adjust our actions because of that?
