Diagnose this ...

[IBob]

"Say what!!???    Where's my razor!! "

 

It actually wasn't his: he was just so good at wielding it, it got labelled with his name..........

[Garfly]

Well, there ya go! 

 

True history, like the wind, ne'er blows in a steady stream.

 

(Though there're them what say for a craft inside a parcel of air, the wind, though moving strong, may ne'er blow at all.)

Edited October 17, 2020 by Garfly

[Yenn]

My tiny tach is faulty. This was the seond time that it had re set itself from 2 pulses per rev to 1 pulse. Resetting on the ground is easy and I am back to correct rpm. The tach works on only one mag so if OMEs' problem arose I would have had a small rev drop or zero rpm.

I still think that given the facts from OME that with light and variable winds during a high pressure time and in a coastal area, that 30 minutes coule result in several miles out in distance travelled.

[Garfly]

Anyway, this has been a fun thread. It's got us back to thinking through the basics; even if our hard task master is definitely deserving of a job at CASA and RAAus.  How'd ya like a crack at the Human Factors exam OME?  I heard of one instructor who'd tell his students taking HF "If you get all these questions 'right', I will not, in conscience, be able to pass you."  LOL.

Edited October 17, 2020 by Garfly

[old man emu]

27 minutes ago, Garfly said:

How'd ya like a crack at the Human Factors exam OME? 

Not possessing the necessary physique to be able to soar with the eagles, I haven't had cause to look at the HF syllabus in detail. However, since HF relating to flying an aircraft is just one application of the same theories and practices that fall under the broad umbrella of safety that also includes workplace and motoring safety, I reckon I could think up a puzzler to test HF application.

 

Someone got a link to the RAAus HF course?

 

Thanks for enjoying the exercise.

[old man emu]

54 minutes ago, Yenn said:

in a coastal area,

I suppose that little bit was a red herring. I was thinking of a flight from Camden to Moruya when I wrote that. Just because I know the airport is right on the beach. Perhaps I should have been thinking of a flight from Camden to Temora or Dubbo when the orographic effects of the coastal escarpment might be less of a factor. 

[spacesailor]

" Anyway, this has been a fun thread. It's got us back to thinking through the basics; ".

It got me thinking ?, IF suspect mag was switched off, No reduction in revs. THEN switch OFF GOOD MAG and GOSH 

NO BLUDI MOTOR.

HELP, Mayday mayday mayday. engine out over water.

spacesailor

[Thruster88]

Thanks for the thread OME. It has made me study up on all things constant speed and manifold pressure. Moruya is a great destination.  

[Garfly]

 

11 minutes ago, spacesailor said:

" Anyway, this has been a fun thread. It's got us back to thinking through the basics; ".

It got me thinking ?, IF suspect mag was switched off, No reduction in revs. THEN switch OFF GOOD MAG and GOSH 

NO BLUDI MOTOR.

HELP, Mayday mayday mayday. engine out over water.

spacesailor

There ya go, nothing more basic than that.

And as you rehearse it all, you'll be thinking to add your aircraft ID, altitude, position/direction, endurance and POB to your Mayday - if time permits.   (Thankfully, in OME's scenario ... it permits.)

How useful is that!?   😉

[old man emu]

2 hours ago, Yenn said:

it had re set itself from 2 pulses per rev to 1 pulse

After checking the earth connection, my next step was going to be to check that it was set to the correct sampling rate.

[Bosi72]

Pilot error - poor planning

The GPWT is measured at the center of the grid and you've flown closer to the edges.

To get more accurate winds, you would have to take average between neighboring and flight path grids.

My 2c

 

[old man emu]

WILL YOU STOP GOING ON ABOUT THE WIND!

 

The high barometric pressure and "winds light and variable" was meant to indicate Nil Wind conditions in order to eliminate that factor from the exercise. If you want to go on about the wind, next time I'll give the angle of the dangle, in radians, caused by the winds blowing high up McTavish's kilt.

[M61A1]

40 minutes ago, old man emu said:

WILL YOU STOP GOING ON ABOUT THE WIND!

 

 

Why.....It's the simplest and most logical reason for indicated speed not matching ground speed.

You said it a simple solution.

[old man emu]

4 minutes ago, M61A1 said:

Why.....

Because when I posed the question, I didn't want that to be an answer. I wanted it eliminated immediately from the diagnostic process.

[Blueadventures]

Wind is always the number 1 factor expected for reduced GS 
to expected.

[Yenn]

Who does a mag test in climb? It is a regular part of my flying and tells me more about mag workings than a check before take off.

[Garfly]

Well, they do say a mag-check should be part of any rough-running trouble-shooting. (In case one circuit's bad, and misfiring, whilst the other's still good, and could see you home, alone.)

(Sorry Spacesailor, for you it's back to that Mayday call!  LOL)

Edited October 18, 2020 by Garfly

[APenNameAndThatA]

On 17/10/2020 at 11:22 AM, old man emu said:

Theoretically, quite so, but it depends on where the centre of mass of the fuel load is in relation to the CofG of the aircraft, and also the weight loss from fuel burn in 30 minutes at 75% power. 

 

If one accepts that altitude would have changed, would that negate a search for the reason for the altitude change? Would not discovering a dud magneto be the result of that search?

That's about 7 kg of fuel. So, your question is wrong. People keep mentioning the wind because it is the correct answer.

[APenNameAndThatA]

3 hours ago, old man emu said:

Because when I posed the question, I didn't want that to be an answer. I wanted it eliminated immediately from the diagnostic process.

You wanted to eliminate it from the question. Which is why you, and your question, are wrong. If the engine lost power, you would have lost height. Instead you said that the aircraft was slow. The way the question was written, wind is the correct answer. Thanks for coming.

[APenNameAndThatA]

By having the aircraft maintain height, you actually eliminated a magneto failure from consideration. 😂

[old man emu]

46 minutes ago, APenNameAndThatA said:

Thanks for coming.

Made ya think, didn't I?

[M61A1]

1 hour ago, old man emu said:

Made ya think, didn't I?

Pretty sure you don't want to know what it made me think....😵

[old man emu]

OK. Let's call quits. I set a scenario without ensuring that it was completely debugged. I'm sorry that no one had the ability to look for the main point, but focused on wind, fuel and trim.

 

I was going to pose another question on something else, but I can't be bothered to minutely inspect every syllable to ensure that what I write is blatantly obvious.  Maybe I should work backwards. Provide the answer, then ask people what the question is.

[Bosi72]

You said it was Sunday.. Notam said Avgas not available on the weekends, so you drove to the nearest petrol station with jerry cans and filled with low quality unleaded

🙂

 

After the takeoff, you forgot to lean the mixture and got bottom spark plugs fouling..

 

If it's not the weather, then you're lucky to be alive 🙂

 

Cheers

 

[M61A1]

12 minutes ago, old man emu said:

I'm sorry that no one had the ability to look for the main point,