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Old 6th Jan 2019, 22:33
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Pilot DAR
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Join Date: Aug 2006
Location: Ontario, Canada
Age: 58
Posts: 4,194
Reading the instructions

As readers here may have noticed, I kind of harp on the idea that a pilot should read the the flight manual (the instructions). (By the way, I write "flight manual", while also considering the "POH", I'll get back to that). Every now and then (okay, I'm guilty more than once myself) a pilot launches into the sky in an aircraft, not completely aware of the information in the flight manual applicable to the flight. Has anyone else noticed this?

I found during my training, that training was emphasized, the flight manual, not so much. Okay, it was only a 152, and the flight manual was not really that thick, so it was easier just to do what my instructor told me. In the 152, it seemed to have worked. That said, I was a curious lad, and I would hang around the airport on rainy days, hoping to listen in the shadows to sky god conversation, or to find something to read, so I did read flight manual from time to time.

For any certified aircraft manufactured since the mid 1970's, the flight manual is probably "approved" by the authority of the nation of manufacture (commonly the FAA). In the case of Cessnas, one can often read somewhere in the front of the Owners' Manual/POH words like "this document constitutes the FAA approved flight manual" - good, we know where we stand with that.

I once had to fly performance flight testing for changed propellers in a Piper Twin Comanche. I reviewed the POH for performance information. I could not make the baseline aircraft climb anywhere near the POH values, and the mod did not improve on that much. Problem; how do I show compliance of the aircraft to the climb performance charts, when it did not comply? My learned mentor told me: "Pilot DAR, look for the performance information in the FAA approved flight manual for the airplane" - it was kind of like having Yoda tell me something. I knew that he must be right, but what was I missing? Aha! Piper issued both a POH, and an FAA approved flight manual for the Twin Comanche. The POH is really flashy, the FAA approved flight manual much less so - but approved. I was required to consider the FAA approved flight manual, the POH, was not approved, and therefore of unknown authority. The FAA approved flight manual for the Twin Comanche provides performance information for altitude loss in a stall, (an FAA requirement for certification) and nothing else. Good, there is no FAA approved climb performance data for the Twin Comanche, so the basis of my test changes favourably.

Another time, I test fly a brand new Found Bushhawk on skis. The aircraft had been delivered from the factory to the airport where I flew it. This time, I read the flight manual from the beginning, to the beginning of the supplements, which I did not read ('cause I know about radios right?). The speeds in my flight test were in conflict, the speed ranges on the ASI did not correspond to the speed in the flight manual. Hmm... I flew the test with the conservative speeds, though perplexed, what was I not understanding about this - and, I'm going to look stupid when someone (Yoda) points out to me what I have not figured out yet! After the flight, and needing a little more data, I read further into the flight manual supplements. I skipped the supplement for floatplane, as I was flying a skiplane. There was no skiplane supplement ('cause that was what I was flight testing for), then, I saw a supplement for STC installed fowler flaps. Hmmm, the plane I just flew has fowler flaps, I saw them! That must mean that this supplement applies - but when did this plane get an STC installed, it's brand new! It turns out that the Found company holds an STC for it's own plane for a fowler flap installation, replacing the plane flaps of the original design, and it left the factory with this modification (well, original build, installed. But the flight manual did not really point the pilot to this difference. There was much changed information for the aircraft with fowler flaps, including speeds. The ASI was correct, for the fowler flap version of the aircraft. I felt I was standing up to my waist in the swamp of Dagobah, with Yoda just shaking his head that I'd flown a flight test using the wrong basic data.

As a fairly new pilot, I'd flown the Cessna 310R with three passengers. One beside me, and two in the middle row. It seemed nose heavy. When I began the prep for my next flight with the same passengers, I consulted the flight manual, and really did a W&B. The number did not work out. After a few tries, I sought assistance from another flight crew in the lounge. when they worked through it with me, it seems that the way the plane was loaded required me alone in the front, one mid row pax, and two in the back row. I sat them there, and the plane flew well!

During a checkout for rental of a Piper Arrow 3, the checkout instructor had me land into a runway which was suspiciously short, on a hot Florida day. Now being nervous about the takeoff, I informed him that I would lock off the automatic landing gear to assure that it retracted when I selected up and a slightly slower speed, I really wanted it up when sleected. He resisted, displaying puzzlement as to what "locking off" was in the Arrow. I pulled out the POH (okay, I can't be sure now it was also the flight manual, Twin Comanche considered) and showed him the system description, and statement about locking the gear off for a short field takeoff. I'm pretty sure he'd never seen this before - and he was checking me out!

There are a couple of types I have encountered where the only difference between two models of the type is the flight manual - often written to comply with the requirements of a different authority, for that authority's approval - the plane itself is the same.

So, to stimulate discussion, I've honoured up about a few of my many flights which were too casual about reading the flight manual. Would anyone else like to tell us about how they used (or didn't use) the flight manual, and what they learned from that? I'm hoping to renew the sense of importance of reading the instructions before you fly the plane!
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