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Threshold Time & Distance


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Hi all,

 

I was hoping for some clarification regarding the Threshold Time & Threshold Distance in the Aircraft Editor. I'm setting up the EDTO data for a B777-300ER in the Aircraft Editor. As per our company operation manual, ETOPS data for the B777-300ER in our fleet are: 60 mins/423nm; 120 mins/836nm; 180 mins/1249nm and 207 mins/1435nm. At work, company flight plans always uses 180 mins.

 

I need to have a more clearer understanding of what the Threshold Time and Threshold Distance is and how those figures are obtained. In the the Aircraft Editor (1st screenshot), it has the figures as 60 min / 485nm. Are those figures correct for a B777-300ER?? Or should I be using these figures: 60 mins / 423nm as outlined in our company operation manual??

 

In 2nd screenshot, I was planning a flight from KSFO to NTAA. I'm using the ETOPS 180 mins rule, I see the ETP 1 however, I also see a CRP 2. What is CRP 2?? Is that the same as ETP 2 but under a different name??

 

In 3rd screenshot, I also noticed that when planning the same route (KSFO-NTAA), when I go the Advanced tab, I select the EDTO scenario of 180 mins, however, PFPX prompts me to do a EDTO setup where it normally allows me to Compute Flight. Now, the only way I can bypass that EDTO setup option is to click on the Compute button on top. Is there something I'm doing wrong when planning an ETOPS flight?

threshold Dist-1.jpg

ETP-1.jpg

setup EDTO-1.jpg

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The Threshold Time is set by the governing authority and is generally 60min and whereby an aircraft should be within that time limit from an adequate airport. Exceeding that 60min requires EDTO approval.

 

Diversion speed and distance are calculated at one engine out operation. PFPX will use the data from the performance file, however you need to re-enter the 60min threshold time to populate the figures. Here this returns a speed of 401kt and 401nm, however as you have your realworld data at hand you could use those figures.

 

In your screen shot it can be seen that your route does not pass fully through the 180min range rings and you are outside of the EDTO requirement for a portion of the flight. Instead of an ETP2 entry you now have a Critical Point where you are equidistant from two diversion airports.

 

As your route does not comply with the EDTO rule as above then the EDTO planning box remains red.

 

 

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10 hours ago, srcooke said:

In your screen shot it can be seen that your route does not pass fully through the 180min range rings and you are outside of the EDTO requirement for a portion of the flight. Instead of an ETP2 entry you now have a Critical Point where you are equidistant from two diversion airports.

 

As your route does not comply with the EDTO rule as above then the EDTO planning box remains red.

 

 

So that I understood correctly. If I were to plan the route to where both the PHTO and NTAA 180min ring over lap each other (like with KSFO and PHTO), I should then get ETP 2 to display??

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Yes that is correct, the route must remain within the 180min radius.

 

The options are to select other EDTO alternates giving the overlap if possible, change the route or if authorized use an increased EDTO range such as 207min for the North Pacific.

 

Here is a link to Belisar's excellent ETOPS GUIDE.

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