Rusty pilot--margin for error question

[Richard-B]

After receiving my private ticket in 1993 and having been current only once since that time--in about 2003--I soloed again earlier this week. I'm still getting back into the swing of things but I'm really enjoying it. My few hours in the plane over the last 2-3 weeks have led to some questions.

I tend to add some margin for error in altitude and airspeed. For example, I'm not yet comfortable with climbing out at 60 knots (172M), the speed at which my instructor tells me to climb, and I find myself adding 10 kts of "cushion". Similarly, I am almost always high on final approach, and usually a bit too fast. It's almost a subconscious habit of adding a little margin for error. My initial training back in the early 90s was at a little airport way out in the country and I'm not yet accustomed to my current home base in the suburbs of Atlanta. Perhaps all of the buildings, poles, etc. are more mentally distracting than I should allow them to be.

How much margin of error is built in to the takeoff and landing speeds and the PAPI/VASI glideslope? How concerned should I be with something quickly and unexpectedly going wrong if I'm at 60 kts on takeoff and landing?

 

[RyanB]

I'm not yet comfortable with climbing out at 60 knots (172M), the speed at which my instructor tells me to climb

That’s too slow. You should be climbing out at Vy under normal circumstances, which in the 172M is just shy of 75kts (or 80mph). As to your last question, if you’re on the glide path for any given runway, you will be guaranteed obstacle clearance.

 

[JScarry]

It’s possible that you misunderstood your instructor. I have a few hours in 172N and those speeds sounded way low to me. I checked the manual and it says that Normal climbout is 70-80 KIAS. Short field is 59 KIAS.

Normal approach is 60-70 KIAS over the threshold. Until then don’t go below 75 KIAS. Short field is 60 KIAS.

 

[Ravioli]

I tend to add some margin for error in altitude and airspeed. For example, I'm not yet comfortable with climbing out at 60 knots (172M), the speed at which my instructor tells me to climb, and I find myself adding 10 kts of "cushion".

Power management is crucial in both take off and landing. Don't "pad" the book numbers, strive to be right on them. They exist for a reason.

Meaning, going too fast on take off means your probably getting less than book climb out at Vx and Vy. That's "not good". Too slow is potentially worse.

On landing too fast means longer roll outs and potentially crazy amounts of extra "flair". That's not gonna hit your intended point of landing, floating, and potentially over running the runway or braking like mad. Too slow you'll get unexpected sink rates, and more pitch and power changes when you should be on a stabilized approach.

Might want to fly with another CFI, or at least spend an hour of ground instruction with the POH to make sure you're on the same page.

 

[Richard-B]

Thanks for your insights. There are a couple of factors at play and I appreciate your perspective on how to manage them.

It has been a long time since I flew very much--more than 25 years. I have probably 15-20 landings since 1993 when I finished my private ticket, and only 6-8 since about 2003. So one factor is that I'm simply out of practice. Another is that 90% of my time in the pilot's seat has been in a 150 and now I'm in a 172 which I'm told has a pretty new engine, so whatever "feel" I might have from my earlier flying time is somewhat different than what I am experiencing now.

After thinking over the previous posts a bit, it's quite possible that I simply misunderstand what my instructor is telling me. Some time on the ground with some specific questions & discussion along with a mental rehearsal will probably do wonders. Doing some pattern work until I'm comfortable in the plane again and hitting the numbers--speeds and altitudes at different points in the pattern--would be time well spent. Even though he has signed me off for solo flight, I'm going to schedule some more time with the instructor before I head off somewhere on my own. Better safe than sorry.

Thanks again for your feedback.

 

[Huckster79]

Thanks for your insights. There are a couple of factors at play and I appreciate your perspective on how to manage them.

It has been a long time since I flew very much--more than 25 years. I have probably 15-20 landings since 1993 when I finished my private ticket, and only 6-8 since about 2003. So one factor is that I'm simply out of practice. Another is that 90% of my time in the pilot's seat has been in a 150 and now I'm in a 172 which I'm told has a pretty new engine, so whatever "feel" I might have from my earlier flying time is somewhat different than what I am experiencing now.

After thinking over the previous posts a bit, it's quite possible that I simply misunderstand what my instructor is telling me. Some time on the ground with some specific questions & discussion along with a mental rehearsal will probably do wonders. Doing some pattern work until I'm comfortable in the plane again and hitting the numbers--speeds and altitudes at different points in the pattern--would be time well spent. Even though he has signed me off for solo flight, I'm going to schedule some more time with the instructor before I head off somewhere on my own. Better safe than sorry.

Thanks again for your feedback.

good job! Sounds like you are doing it tight! Welcome back!!!

If you really want to get proficient at TO and landing once your rust is off, find a school for your Tail wheel endorsement. Preferable in a low powered one. Honest. You will learn so much the 172 just can’t teach you easily in a low powered tail dragger. And when you get back in the skyhawk, even if you never fly TW again you will have a much better grasp of energy management and that “padding” is no bueno!

after becoming a TW pilot I get in the 172 in any doable wind condition without a bit of sweat- gusty crosswinds? Let’s go... before my TW I didn’t have the same confidence I do now...

 

[bobmrg]

Other than snap rolls, there are few things in flying that happen instantaneously. My mantra with students was always "Don't just do something, sit there!" The book landing speeds of Vs 1.3 on final and vs x 1.3 over the threshold afford you a cushion, but that is the only place I can think of where a "margin of error" is built in.

Bob Gardner

 

[Davidl13]

Good thinking on wanting to stay safe... It doesn’t sound like you know the V speeds of your aircraft. Before any flying is done you should
Know them, memorize them, print them out and Tape them to your dash... until they are memorized and second nature... operate by them... add 1/2 gust factor on landing if it is appropriate... Test pilots figured all of this out for you (and me)... use that data... know thy aircraft...

 

[exncsurfer]

... As to your last question, if you’re on the glide path for any given runway, you will be guaranteed obstacle clearance.

I took his second question as more along the lines of, if the engine fails. The glide slope indicator while giving obstacle clearance would be too low for any extra margin of safety in that case and perhaps a steeper approach angle would be preferable if making the runway is the goal.

 

[Huckster79]

I took his second question as more along the lines of, if the engine fails. The glide slope indicator while giving obstacle clearance would be too low for any extra margin of safety in that case and perhaps a steeper approach angle would be preferable if making the runway is the goal.

that makes sense and another cure to that concern would be not making a 747 sized pattern... keep her in glide range all of pattern.

 

[Richard-B]

I had, indeed, misremembered what my instructor said.

My son took video of portions of our flight and when I went back & looked at it I discovered that I missed something the instructor said . . . twice.
On the first takeoff he said to rotate at 60 and climb at 70 and he repeated it a short time later. I haven't double-checked the POH in the plane but an online copy has Vr = 55, Vy = 70-80. Other online references list Vr = 55, Vx = 64, and Vy = 78. I did a few circuits this evening and was quite comfortable rotating at 60 and climbing out at just under 75 kts.

I haven't been through all of the video yet but I think that in the practice for recovering from departure stalls he had me set it up by climbing at 60.

 

[sarangan]

After receiving my private ticket in 1993 and having been current only once since that time--in about 2003--I soloed again earlier this week. I'm still getting back into the swing of things but I'm really enjoying it. My few hours in the plane over the last 2-3 weeks have led to some questions.

I tend to add some margin for error in altitude and airspeed. For example, I'm not yet comfortable with climbing out at 60 knots (172M), the speed at which my instructor tells me to climb, and I find myself adding 10 kts of "cushion". Similarly, I am almost always high on final approach, and usually a bit too fast. It's almost a subconscious habit of adding a little margin for error. My initial training back in the early 90s was at a little airport way out in the country and I'm not yet accustomed to my current home base in the suburbs of Atlanta. Perhaps all of the buildings, poles, etc. are more mentally distracting than I should allow them to be.

How much margin of error is built in to the takeoff and landing speeds and the PAPI/VASI glideslope? How concerned should I be with something quickly and unexpectedly going wrong if I'm at 60 kts on takeoff and landing?

I personally don't see any problems with your technique as long as you are doing that purposefully and consistently, and not due to sloppiness. If you are in a hurry to climb, fly at Vy. If there are obstacles to clear, then fly at Vx. If neither, then pick something a bit faster. It will give you a lower pitch and better visibility. For landings, I generally teach students to fly steeper than 3-deg. But that requires the pilot to gauge the angle without the aid of a VASI, and that takes experience. Dragging the airplane above the roofs and treetops gives me the creeps, even if it is at 3-deg. I would much rather see all white on the VASI and then transition to red as I cross the fence. I am not worried about engine failures as much as a gust of wind or a downdraft that can put you uncomfortably close to obstacles. Squirrelly winds are more likely close to the ground, and a steeper approach will minimize your time through this zone. Anyway, that's just my opinion. I am sure you will get others opinions too. Most of all, ask yourself why a recommendation exists before blindingly following that recommendation.

 

[bobmrg]

I had, indeed, misremembered what my instructor said.

My son took video of portions of our flight and when I went back & looked at it I discovered that I missed something the instructor said . . . twice.
On the first takeoff he said to rotate at 60 and climb at 70 and he repeated it a short time later. I haven't double-checked the POH in the plane but an online copy has Vr = 55, Vy = 70-80. Other online references list Vr = 55, Vx = 64, and Vy = 78. I did a few circuits this evening and was quite comfortable rotating at 60 and climbing out at just under 75 kts.

I haven't been through all of the video yet but I think that in the practice for recovering from departure stalls he had me set it up by climbing at 60.

There are procedures, set out by the manufacturer in the POH, and there are techniques, based on an individual instructor's opinions and practices. Do not get hung up on what one instructor calls for, because the next instructor you encounter will probably teach another technique. Stick with the POH.

Bob Gardner