What approach speed to use floating

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BJC

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Do folks not check for airspeed coming alive and abort takeoff if either airspeed indicator is dead,
I check, and have, on a couple of occasions, noted that the ASI wasn’t working, but continued the takeoff anyway.
the idea of taking off with a cover on seems a bit bizarre.
Bizarre things happen.

As a student pilot, I was required to fly without airspeed indication. Aeronca 7AC. Not a big deal.


BJC
 

addaon

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Oh, definitely did my time flying without airspeed as a student, and agree that it's no big deal. But taking off with a piece of required equipment in a failure state is a no-go for me. Partially because (a) if I just forgot the cover, what else did I forget? and (b) if it's because of a mechanical failure, how do I know it didn't have other consequences (e.g. something chewing through a pitot tube might have wanted dessert)?
 

TarDevil

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Do folks not check for airspeed coming alive and abort takeoff
Certainly should. Can't remember why our student got aloft with it inop.

We were extremely lucky to have our CFII. Older, extremely experienced. Flew all over the south Pacific in DC3's.
He took our students up when ice was forming on tree limbs. When necessary, he'd take the plane into the maintenance shop to thaw, then back up again.
Primary students were exposed to actual IFR.
They had to land with the prop stopped.
They had to fly the pattern with the trim maxed up and down.
Spins were mandatory.
I already had my ticket when I started managing the FBO but I still took lots of dual from him.
 
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proppastie

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Do folks not check for airspeed coming alive
good point....I think once was ice, and once at Appleton coming out from Oshkosh .......I remember not wanting to mention over the radio why I needed to return because of possible violation issues so I just kept on going to an uncontrolled field a little down the line and landed.....In the Cherokee it was no big deal....a little more interesting in the Mooney
 

Kiwi_

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In response to the initiator of this post - call it "two cents worth" on a rainy day when I would rather be fishing. Besides, I have very fond memories of the little 'Cherokee 140'.

Certification requirements for the PA28-140 (even back in the 60's) required something along the lines of CFR23.2130, which requires the applicant - Piper Aircraft - to (and I paraphrase):

"... determine the distance, starting from a height of 50 feet (15 meters) above the landing surface, required to land and come to a stop. The approach and landing speeds, configurations, and procedures, which allow a pilot of average skill to land within the published landing distance consistently and without causing damage or injury, and which allow for a safe transition to the balked landing conditions of this part accounting for stall speed safety margin and minimum control speeds."

Imagine an infinitely long paved level runway on a calm day. Apply the the technique in the "Owner's Handbook" and you should be able to consistently land in the promulgated distance stipulated in the chart "Landing Distance vs Density Altitude."

There is no mention where to touch down on the runway - the applicant (Piper) is only required to determine the distance and specify the configuration used and the safe procedures applied to achieve it. Alas not all runways are infinitely long.

The "Handbook" makes reference to configurations and techniques which are not scheduled in the charts. As I recall there is little advice for the effect of wind, landing on dry/wet grass, loose metal, sand, snow and so forth. The pilot is required to establish his/her own safety factors to account for such changes in landing distance.

On aerodynamic braking (holding the nosewheel off the runway during the landing roll). The use of aerodynamic braking is applicable only for deceleration to 60 or 70 percent of the touchdown speed. At speeds less than 60 to 70 percent of the touchdown speed, aerodynamic drag is so slight as to be of little use, and wheel braking must be utilised to produce continued deceleration. Note also the considerable reduction in directional control and diminished ability to react to crosswind gusts with the nosewheel off the runway.

On alpha. The wing will always stall at a fixed (critical) angle of attack, but at many demonstrable airspeeds. A good indication that one is approaching critical alpha is the ASI. Install an alpha meter by all means, but what will it be indicating for 95% of the flight and are you practised in using such a device? The ASI works well and maintaining a 30% margin on the stall during final approach has been demonstrated as being safe for pilots like me 'of average ability' (sometimes I struggle to be average).

Loss of ASI on the take-off roll. Reject (abort) the take-off if safe to do so. Why take a significant failure airborne?

Landing on the numbers. Are you practising for precision landing competition or aiming to land on a safe part of the runway? The -140 'Handbook' advises to reduce speed during the 'flareout' and to contact the ground close to the stalling speed (55-65mph). This reads as 'float' and is a specified technique promulgated by the manufacturer. Which you are applying - good for you.

Technique on final approach. Select an "aiming point" - likely before the chosen touchdown point. Options:

(1) Pitch to adjust approach speed, power to adjust rate of descent; or

(2) Pitch to maintain the fixed aiming point, power to maintain desired approach speed

Whichever technique you apply, adjust the aiming point to allow for the flare and touch down where you desire. You can put a bit of tape on the stanchion between the front windscreens to represent your desired touchdown point when stable at approach speed in the landing configuration. Keep 'the numbers' under this tape until the flare and power reduction. Practise and adjust accordingly.

Apply the correct technique and accuracy will come with practise.

It's stopped raining - got to take the covers off the boat.
 

Victor Bravo

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Do folks not check for airspeed coming alive and abort takeoff if either airspeed indicator is dead, or if they disagree? Pitot icing in flight is a real threat, I get it, but the idea of taking off with a cover on seems a bit bizarre.

If you have a bug in the pitot, or a faulty ASI, or accidentally leave the cover on... you will essentially be taking off with a cover on, and in a real-world risk situation. So definitely practice it ahead of time.
 

PiperCruisin

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If you have a bug in the pitot, or a faulty ASI, or accidentally leave the cover on... you will essentially be taking off with a cover on, and in a real-world risk situation. So definitely practice it ahead of time.
Had mine ice over once. My instrument instructor had me flying partial panel at night half the time so it didn't worry me much. My current plane has pitot heat though.
 

PiperCruisin

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"... determine the distance, starting from a height of 50 feet (15 meters) above the landing surface, required to land and come to a stop. The approach and landing speeds, configurations, and procedures, which allow a pilot of average skill to land within the published landing distance consistently and without causing damage or injury, and which allow for a safe transition to the balked landing conditions of this part accounting for stall speed safety margin and minimum control speeds."
POH at my typical weight and DA says a ground roll of 550 ft and distance over 50 foot obstacle of 1150 feet. With no wind and moderate braking (not going for maximum brake wear), I stop in about 1400' from threshold (no wind).

The ground roll distance seems somewhat reasonable if you're going for maximum braking. If they start at 50' above the threshold and stop in 1150 feet, that seems iffy at recommended airspeeds.
 

Pops

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I had an engine out on takeoff with a Cherokee one time. Mud dauber plugged the right fuel tanks vent up in the 30 + minutes that I was at KCRW. Runup was good. Taking off on runway 33 ( closed a few years ago) and got about 30 /40' and the fuel pressure gauge went to zero and the engine quit. Hard nose down and pulled full flaps at the same time. Go stopped at the intersection of 22/5 easily that's maybe 3K or 3500'. About the last turn of the blade of the prop after touching down the engine started with the fuel pressure coming up. ( gasket on fuel cap leaking in some air). Anything over 2000 RPM the engine would quit. Yep, fuel boost pump was on.
Why I always refuse an intersection takeoff.
 

Kiwi_

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If they start at 50' above the threshold and stop in 1150 feet, that seems iffy at recommended airspeeds.

The Piper company test pilot demonstrated the 'Owners Handbook' performance figures in a 'new' aeroplane for the purposes of certification back in the '60's.

The applicable chart in the PA-28-140 'Owners Manual' (Landing Distance vs Density Altitude) clearly stipulates 'Maximum Braking' as the relevant technique. In your post above you specifically state that you apply "moderate braking" to reduce brake wear. Ergo, you cannot expect scheduled performance figures if you do not apply the technique stipulated by the manufacturer. Hence your observation that the manufacturer's figures appear "iffy".

Just as you are at liberty to apply your own 'safety factors' for the effects of wind, runway surface, slope and so forth, so are you at liberty to establish your own 'safety factors' for the landing technique that you choose to adopt.
 

Dan Thomas

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The Piper company test pilot demonstrated the 'Owners Handbook' performance figures in a 'new' aeroplane for the purposes of certification back in the '60's.

The applicable chart in the PA-28-140 'Owners Manual' (Landing Distance vs Density Altitude) clearly stipulates 'Maximum Braking' as the relevant technique. In your post above you specifically state that you apply "moderate braking" to reduce brake wear. Ergo, you cannot expect scheduled performance figures if you do not apply the technique stipulated by the manufacturer. Hence your observation that the manufacturer's figures appear "iffy".

Just as you are at liberty to apply your own 'safety factors' for the effects of wind, runway surface, slope and so forth, so are you at liberty to establish your own 'safety factors' for the landing technique that you choose to adopt.
If a pilot touches down at speeds above where he should be, maximum braking will skid the tires and maybe blow them out. Numerous times in this discussion this has come up; pilots are not slowing the airplane down before they get into ground effect. It's a skill that's not being taught or caught anymore.
 

PiperCruisin

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The Piper company test pilot demonstrated the 'Owners Handbook' performance figures in a 'new' aeroplane for the purposes of certification back in the '60's.

The applicable chart in the PA-28-140 'Owners Manual' (Landing Distance vs Density Altitude) clearly stipulates 'Maximum Braking' as the relevant technique. In your post above you specifically state that you apply "moderate braking" to reduce brake wear. Ergo, you cannot expect scheduled performance figures if you do not apply the technique stipulated by the manufacturer. Hence your observation that the manufacturer's figures appear "iffy".

Just as you are at liberty to apply your own 'safety factors' for the effects of wind, runway surface, slope and so forth, so are you at liberty to establish your own 'safety factors' for the landing technique that you choose to adopt.
1. I don't see the difference "new" vs 50 years old will make as far as landing configuration goes. Maybe my gap seals and hoerner wing tips make a significant difference though. Maybe someone can prove me wrong and post a video where you stop in 1150 feet starting at 1.5 wingspan above the runway threshold.
2. Maximum breaking or not, the number over a 50' obstacle is still iffy. Perhaps cutting power higher up and bleeding airspeed to avoid the high sink rate and timing it perfectly to minimize float at touchdown is the technique to master. Maybe "average" pilots do this. I doubt it. It would be a good way to plant the tires short of the runway or slam it on like a carrier landing. Dragging it in would be easier and a more common STOL technique.
3. The landing technique specified by the manufacturer is quite vague. I still think they should specify final approach speeds based on landing weight.
 

bmcj

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Do folks not check for airspeed coming alive and abort takeoff if either airspeed indicator is dead, or if they disagree? Pitot icing in flight is a real threat, I get it, but the idea of taking off with a cover on seems a bit bizarre.
That’s still not a guarantee. The very first time I test flew a Rutan Quickie, I harpooned a very large bug immediately after liftoff. The ASI and VSI went from normal to zero. This on a brand new build in a relatively unfamiliar aircraft with non-traditional stall characteristics (being the very first customer built plane, there were no others to gain familiarity in).

I had to it around the area getting familiar with the low speed end, then set up repeated approaches getting progressively slower until the sink rate was acceptable.
 
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Kiwi_

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1. I don't see the difference "new" vs 50 years old will make as far as landing configuration goes.
New tyres, new brakes, clean hydraulic fluid, new master/slave cylinders, uncorroded components, new suspension, new clean pitot static system, new performance flight instruments yet to be affected by elastic hysteresis, and so forth.

Maybe my gap seals and hoerner wing tips make a significant difference though.
Ah, ok - the plot thickens. A non-standard landing technique (ie, not the one specified on the PA-28-140 landing performance chart) in a modified aeroplane is not achieving the scheduled performance figures that were obtained by the manufacturer in a basic unmodified aircraft operated as per the charted criteria (!)

Maximum breaking or not, the number over a 50' obstacle is still iffy.
That's fine as an opinion - is there any quantifiable data to support this assertion for an unmodified aeroplane or is it a 'gut feeling'? Piper took the liberty of consolidating their measured data into a graph for a 'stock' PA-28-140 aeroplane that they were testing and published it in the 'Owners Handbook' in order to certify the machine. Perhaps you might like to canvas Piper Aircraft for the original test cards if you feel that their promulgated landing data is questionable, as this would constitute a matter of safety?
The landing technique specified by the manufacturer is quite vague.
I totally agree.
 

Victor Bravo

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There is no POH or set procedure for how to pick up girls in a bar, how to make people laugh doing stand-up comedy, how to have as wildly successful of a restaurant as Wolfgang Puck, how to be a billionaire like Warren Buffett, or how to be happy in life. You cannot graduate Green Beret, SEAL, or Delta Force training just from using the manual. And trust me, you sure as heck cannot sing like John Lee Hooker by using a book.

And so it is with landing an airplane. You need practice, trying different things, and developing an instinct... "feel the force" as Obi-Wan said.

(Remember what Yoda did to the sacred books in the last Star Wars movie... and why he did it)
 
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