PET AND PNR CALCULATIONS

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Captain.huzaifa
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PET AND PNR CALCULATIONS

Hi guys
Need some help here with a complex PET/PNR calculation

The question states as follows"

Given:
Ground speed out 320knots
Ground speed home 400knots
Total Distance is 800NM
PET distance is 425NM
Safe distance is 02 hours 55 minutes

WHAT IS THE TIME TO THE PNT?

OR ALTERNATIVELY

Given:
Ground speed out 320knots
Ground speed home 400knots
Total Distance is 800NM
PET distance is 425NM
Safe distance is 02 hours 55 minutes

WHAT IS THE DISTANCE TO THE PNR?

Much appreciated
Huzaifa
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Re: PET AND PNR CALCULATIONS

Hi Huzaifa,
Given:
Ground speed out 320knots
Ground speed home 400knots
Total Distance is 800NM
PET distance is 425NM
Safe distance is 02 hours 55 minutes

WHAT IS THE TIME TO THE PNT?
In relation to the above I presume they are asking PET?

The formula goes as follows;

PET(in NM) = (Total distance x Groundspeed Home) / (Groundspeed Home + Groundspeed Out)
PET = (800 x 400) / (400 + 320)
PET = 444nm

You then take the above answer and factor it into the Speed = Distance / Time...320 = 444 / ? therefore your time to the PET is 1.39hrs
Given:
Ground speed out 320knots
Ground speed home 400knots
Total Distance is 800NM
PET distance is 425NM
Safe distance is 02 hours 55 minutes

WHAT IS THE DISTANCE TO THE PNR?
The formula goes as follows;

PNR(in time) = (Endurance x Groundspeed Home) / (Groundspeed Home + Groundspeed Out)
PNR = (2.92 x 400) / (400 + 320)
PNR = 1.62hrs

You then take the above answer and factor it into the Speed = Distance / Time...320 = ? / 1.62 therefore your PNR distance is 518nm. You must remeber that the PET formula gives you a distance because you are using a distance in the formula  You must also remeber that the PNR formula gives you a time because you are using a time in the formula I hope this helps!!

Regards,
PLAOS7
Captain.huzaifa
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Re: PET AND PNR CALCULATIONS

Thanks alot buddy
Appreciate it
Captain.huzaifa
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Re: PET AND PNR CALCULATIONS

Howsit guys
Here goes another one

Assuming TAS and wind components are standard
Total distance 706nm
Distance to PNR 397nm
Endurance 02 hours 55minitues

What is the Time to the PNR?

There did not give TAS or ground speeds or any wind directions
GeorgeB
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Re: PET AND PNR CALCULATIONS

Captain.huzaifa wrote:
Thu Apr 27, 2017 5:45 am
Howsit guys
Here goes another one

Assuming TAS and wind components are standard
Total distance 706nm
Distance to PNR 397nm
Endurance 02 hours 55minitues

What is the Time to the PNR?

There did not give TAS or ground speeds or any wind directions
This is a case of using percentage it seems.

Calculate a percentage of the trip to PET. (100/706) x 397nm = 56.23% Or 0.5623

So endurance of 2hr 55min x 0.5623 = 98.4 mins which is the answer we believe.
SAAFNAV
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Re: PET AND PNR CALCULATIONS

GeorgeB wrote:
Mon Aug 27, 2018 9:13 am
Captain.huzaifa wrote:
Thu Apr 27, 2017 5:45 am
Howsit guys
Here goes another one....
May I please barge in for some help too:

Got this in IR OPS exam.

A-B = 1 200. PET = 60% of total distance, PNR = 84% of total distance.
What is GS from PNR to A. (i.e. GS back). End = 8.24hrs. TAS, wind etc stays constant.

Thanks,

Erich