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  • Tonyjames
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Tonyjames created the topic: PEC

I did my IREX yesterday and got 69%...on one of the questions it asked for the DA with PEC 20. I wasn’t sure if we are to add or subtract the PEC 20 from the published DA....can anyone add some light on the...cheers

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  • John.Heddles
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  • ATPL/consulting aero engineer
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John.Heddles replied the topic: PEC

Depends on how the question and the associated data is presented. Static data is a major part of the flight test program. The data is summarised and presented either as several graphs or tables. How the numbers are to be applied should be specified (in a fairly obvious manner) in the static error data.

An example is shown from a C310R manual I downloaded just now from the net. This is quite typical.

File Attachment:

File Name: C310PEC.doc
File Size:52 KB

Specifically for your exam question, in the absence of the question to review, I can only suggest that the data in the question should have provided the information necessary for your use of the data.

Engineering specialist in aircraft performance and weight control.

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  • Ash3005
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Ash3005 replied the topic: PEC

I was going to open a post for the same thing but I thought replying under here would be more appropriate.

Now, we all know that if the PEC data is missing we add 50 feet to DA. So basically if the question is mentioning missing PEC data things are bit easier. My question is, like Tony mentioned above, what is the DA if its PEC 20(or -20)?
There was no other data in the question. There was basically an aerodrome and runway information along with aircraft PEC, and the question is asking what the DA was. So my understanding is (and please correct me if im wrong), if the PEC data is given than the DA is the published DA?
I mean altitude for DA a pilot sees on his altimeter may change based on the PEC data but if the question is asking for just DA doesn't that mean it is the published DA? I am also kind of confused and my KDR stated that I made a mistake calculating DA and Im suspecting PEC question was the reason.
I like to thank in advance for your help.

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bobtait replied the topic: PEC

I agree that the CASA PEC data can be rather confusing. As John says, it all depends on the presentation of the data. I would argue that, since it is called Pressure Error Correction, a PEC of -20 indicates the correction that must be applied to the altimeter. So take 20ft off the altimeter indication. I suppose if the PEC is given as 20, you would assume it's positive.

The question would be much better if it was accompanied by an actual extract from a flight manual.

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