My last flight

[James331]

So your run up was out of spec and not normal for the plane
You continued

Take off roll was not normal
You continued take off roll

Climb was very much not normal
you left the pattern

What’s wrong with the plane, meh, who cares.

The aircraft isn’t what I’d be thinking about

 

[Torque beast]

Don't take the comments the wrong way. At the end of the day you made it safely back to the ground, and that's all that matters. That you shared the experience with us to help us learn from it is, by me at least, much appreciated.

I agree 100% I am a fairly new pilot and learn A LOT from people like you that have the courage to share things like this. Thanks


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[Dan Thomas]

I subscribe to the gold brake and check static RPM before rollout and so it every time unless I get a no delay. Gives you one more chance to verify the static RPM, it also helps in summer where you can lean until you get max performance before rollout. Some say it damages the prop, donno May be it does May be it doesn’t

It can damage the prop if there is any loose debris on the surface. There's a ring vortex around a stationary spinning prop that sucks up stones and stuff from well behind the propeller and below it. I've seen it. And I've dressed out hundreds of propeller blade nicks from that, too.

Older airports sometimes have crumbling taxiways and runways. Maintenance vehicles track mud and stones onto the surfaces. Sometimes airplanes do that too.

 

[Dan Thomas]

Some airplanes have longitudinal g-meters. If you don't meet the required "G" you abort.

A strong headwind will change that reading and lead the pilot to an unnecessary abort.

 

[Dan Thomas]

I stopped by the A&P today, and there was a problem with the engine after all. The magneto timing was off, causing an unised fuel build-up in the cylinders. I did have fouled plugs.

Typical. Electrical problems are 90% of engine troubles. But "unused fuel buildup in the cylinders?" Nope, just poor and late combustion across some of the cylinder. It would foul the plugs alright. Still, a late mag shouldn't cost 200 RPM. Maybe both were way off. Had it been in for maintenance immediately before that? If so, and they had done mag work, they maybe didn't double-check the timing and mag clamps, or do a static runup.

Though I had wondered if maybe the throttle cable housing clamp at the engine end was loose and had let the housing slip aft, limiting the amount that the throttle would open. Seen stuff like that on carb heat and mix cables too. Inspections that aren't really inspections are far too common.

 

[sarangan]

Missing the low rpm on takeoff was one thing, now you know better, but continuing 7 miles on course instead of immediately returning to the airport could have been a much bigger mistake...



"So what is the 50/70 rule? It's a general rule for GA aircraft that says if you haven't reached 70% of your takeoff speed by the time you've reached 50% of the length of the runway, you should abort your takeoff."

Hah! If I'm not off the ground and climbing at 50%, something is very wrong...

That rule should be rephrased as "70% of your takeoff speed by the time you've reached 50% of your takeoff-distance". Obviously, if the runway is 10,000 ft long, and it takes you 5000 ft to reach 35 knots, things are seriously wrong. Also, that rule comes from a constant acceleration formula, which is not exactly true.

Besides monitoring the rpm, one could also use time. You should know approximately how many seconds the takeoff roll should take.

 

[kgruber]

A strong headwind will change that reading and lead the pilot to an unnecessary abort.

Nope. The headwind is in the calculation. Dassault doesn't make 1st grader's mistakes.

 

[Skyrys62]

Besides monitoring the rpm, one could also use time. You should know approximately how many seconds the takeoff roll should take.

Not arguing.. but it seems that could be affected a lot by load, DA, temperature, etc.?

 

[chemgeek]

Thanks for sharing. This kind of story provides an opportunity to learn.

Keep it simple. Note the typical rpm of the plane you fly (when it is performing nominally) on initial full power application. This is your first indication of proper power development. Second, note the distance of your ground roll and compare with the normal distance predicted by your POH. This is your next indication of power development. Third, note the typical rpm of the plane in a Vy climb at full power. This is your final confirmation of power development or warning of power issues.

Example: My AA-5 should develop 2350+ rpm on initial power application and roll; I should reach rotation speed and break ground in 1000 feet or so, but certainly no more than 1500 feet in any reasonable temperature, wind, or loading condition on a paved runway; I should develop 2500 rpm at Vy on climbout. Missing any of those targets should be a concern. The last time that happened, the climbout rpm was 100-200 rpm too low: an in-flight magneto check revealed a failed magneto, which apparently failed sometime during the takeoff run or initial climbout. Confirmed on the ground after returning to land.

The one other time these checks failed was a takeoff at Piseco Lake, NY (nestled in the southern Adirondack foothills). Initial power application was a go, but ground roll exceeded 1500 feet. (Wasn't anywhere near wanting to fly at 50% of the runway.) Takeoff was aborted. In this case, there was no mechanical cause, just wind shear off the mountain creating a sudden change in wind direction to a tailwind. Takeoff in the opposite direction a few moments later was uneventful.

If you haven't practiced aborted takeoffs (my instructor was a masochist about this, bless his heart), you should. They might save your bacon some day. It's a non-event, and if you have practiced them, you are less likely to be bashful to employ them when necessary.

 

[Pilot Steve]

Yes, I definitely learned some things that will always stick with me when I fly.

Those can be the most powerful lessons. Here is my mag lesson. https://www.pilotsofamerica.com/com...n-decision-you-ever-made-here-is-mine.123983/

But honestly, if you get a nagging feeling something is not right as you are rolling for takeoff, abort. This is why I will nearly always go for a full-length takeoff. The last time I had to abort was when I was flying a controller. and as I was about to rotate something didn't feel right. I called an abort and taxied back to evaluate.

 

[Ozone]

I feel as if every time I read posts like this, that a nice winter read for folks in your situation might come in handy. As was alluded to in an earlier reply, static "short field" runup just before takeoff is a quick way to check if you are making full power. Another option on takeoff is to do a combined soft/short field takeoff by staying in ground effect until you are close to cruise speed and then pull up to Vy (see "book to read" below, for details). This will pop you up to at least 500 agl within a few seconds, giving you more decision time in case you just became an inadvertent glider pilot due to a bad mag.
Book to read: https://www.amazon.com/Contact-Flying-Jim-Dulin/dp/0615209831

 

[Tantalum]

While a normal full throttle on the aircraft yields about 2500 RPM, I was only getting 2200-2300 RPM maximum.

I did not notice the low RPM until climb-out

^that right there is the issue... when you go full power for takeoff you should ALWAYS ALWAYS ALWAYS verify that you are making correct, full power figures. RPM where it needs to be, fuel flow where it needs to be, and manifold pressure (if equipped) where it needs to be. You should have noticed that you weren't making full power right away and aborted. On climb out, being slow, you should have turned crosswind and downwind, told the tower you were having an issue and landed

Checklists are helpful, but there are certain memory items you should know, and always fly the plane first

These are good learning opportunities.

Safe flying.

 

[steingar]

To be honest, it sounds like no harm no foul. Pre takeoff indications were only subtly off, odds are had everything gone all right you would have forgotten about the errant tach reading. Had you shut down before your rotation you might have had an overrun trying to slow it down, so you elected to examine the problem in the air. In the air you saw that the aircraft wasn't normal, turned around, and landed. Bonus points for doing a go around when you saw things weren't right.