ETE Flight Time – Calculations

How to calculate the Estimated Time Enroute
(ETE Flight Time) for a Flight Segment.


1st Step:  Determine the segment distance (Dist) for the flight using aeronautical
charts or tables giving distances between airports.

2nd Step:  Determine your segment cruise groundspeed (GS) – use your E6B air navigation computer and the forecast temperature and wind at your cruise pressure altitude, or use your personal knowledge of the aircraft true airspeed and your accurate estimate of the  headwind or tailwind component at your planned altitude.

3rd Step:  Look up the climb/descent data (TTC, TTD, DTC, DTD) with reference to your planned cruising altitude – use your Aircraft Flight Manual (AFM) Performance Section.

4th Step:  Calculate the segment Estimated Time Enroute (ETE flight time).   The general formula for determining the estimated time enroute is –

ETE(1) = (60 * (Dist – DTC – DTD) / GS) + (TTC + TTD + TAD + AAL + HLD)

(Note:  The ’60’ factor seen in the equations on this page are there to convert hours to minutes.)

where,

Dist = Segment Distance (GCNM; i.e., 312.)
ETE = Estimated Time Enroute (Minutes ; i.e., 77.6)
TTC = Time-to-Climb (Minutes; i.e., 23)
TTD = Time-to-Descend (Minutes; i.e.,18.4)
TAD = Takeoff and Departure (Minutes; i.e., 4)
AAL = Approach and Landing (Minutes; i.e., 5)
HLD = Estimated In-flight Delays (Minutes; i.e., 2)
DTC = Distance-to Climb (Nautical Miles; i.e., 84)
DTD = Distance-to Descend (Nautical Miles; i.e., 99.8)
GS = Cruise Groundspeed (Knots; i.e., 305)

(Note: The above numbers are based on a flight from SAC to LAX in a CE-500 at FL370.)

ETE flight time

Then,

ETE(1) = (60 * (312 – 84 – 99.8) / 305) + (23 + 18.4 + 4 + 5 + 2) = (60 * (128.2 / 305)) + 52.4 = 25.2 + 52.4 = 77.6 Minutes.

However, if we really work at it, we can change the general formula, ETE(1), to the equivalent –

ETE(2) = 60 * (Dist / GS ) + (TTC + TTD + TAD + AAL + HLD) – (60 * (DTC + DTD) / GS)

and, since the 2nd part of the formula (in blue type) is independent of the segment distance, we can separate it out as a constant –

KMins= (TTC + TTD + TAD + AAL + HLD) – (60 * (DTC + DTD) / GS)

= ( 23 + 18.4 + 4 + 5 + 2) – (60 * (84 + 99.8) / 305) = 52.4 – 36.2 = 16.2 Minutes

[Note: In this example, this is the amount your ETE will be off if you estimate your ETE flight time by simply dividing your segment distance by your cruise groundspeed!]

Then, we can simply divide the segment distance by the groundspeed, and add KMins to get the exact ETE Flight Time

ETE(2 )= (60 * (Dist/GS ) ) + KMins = 61.4 + 16.2 = 77.6 Minutes.

If you’d rather work with distances, we can change the general formula, ETE(1), to the equivalent –

ETE(3)= 60 * (Dist + ((TTC + TTD + TAD + AAL + HLD) * GS / 60) – (DTC + DTD)) / GS

Since the part of the formula in blue type is independent of the segment distance, we can separate it out as a constant –

KDist  = ((TTC + TTD + TAD + AAL + HLD) * GS / 60) – (DTC + DTD)

KDist = (23 + 18.4 + 4 + 5 + 2) * (305 / 60) – (84 + 99.8) = 266.4 – 183.8 = 82.6 NM.

Then, we can simply add KDist to the segment distance and divide by the groundspeed to get the exact ETE flight time

ETE(3) = (Dist + KDist ) / (GS/60) = (312 +82.6) / (305/60) = 77.6 Minutes = 1.29 Hours.

Note:  The above constants, KMins and KDist , are valid only when the actual flight is flown at the cruise altitude and with the cruise groundspeed, TAD,  AAL and HLD  used for their calculation.

Use calculated ETE Flight Time to determine trip cost –

Step 3: Determine the cost of the trip after rounding the flight time to the nearest tenth –

Cost = ETE * Cost per hour = 1.3 Hours * $1,575 = $2,048.


Click Here  for information on how to
calculate the fuel usage for a flight segment.


Disclaimer

FlightComp Systems does not recommend or advise that any operator use this information as a sole resource for any preflight planning activity.


 

20 Responses to ETE Flight Time – Calculations

  1. Hello there, just became alert to your blog through Google, and found that it’s really informative. . . I’ll be grateful if you continue this in future. Many people will be benefited from your writing. Cheers!

  2. You’re so cool! I don’t suppose I’ve read through anything like this before. So great to find somebody with original thoughts on this subgject matter. Really.. thank you for startng this up. This web site is one thing that is needed on the web, someone with a little originality!

  3. Wow, this is a good article … my sister is analyzing these kinds of things … I’m going to let her know.

  4. Enjoyed every bit of your blog. Really thank you! Keep writing.

  5. Thank you ever so much for this post. Really Cool.

  6. Very neat blog article. Much thanks. Fantastic.

  7. I’m grateful for this blog.

  8. Thanks for sharing. This is a fantastic blog. Much thanks again. Great.

  9. It’s difficult to find well-informed people on this particular subject, but you sound like you know what you’re talking about! Thanks.

  10. A round of applause for your blog article.Thanks Again. Great.

  11. amature says:

    Major thanks for the blog post. Really looking forward to read more. Really Cool.

  12. view says:

    I just want to say I’m new to blogs and absolutely loved your web site. Very likely I’m planning to bookmark your blog . You surely have remarkable articles. Thanks a bunch for sharing your blog.

  13. It was a pleasure finding your site . . . I was hoping to find something new on this topic and I was not dissatisfied . . . Your ideas on this topic are enlightening and an excellent help to us. Thank you for taking the time to create this and for sharing it.

  14. Great content on this page, truly helpful.

  15. Seriously fantastic blog site. I absolutely love the information.

  16. Seriously marvelous blog, website. I truly enjoyed the content of this page.

  17. Wow! thanks for sharing this information! This is great and I enjoyed sharing it with my friends.

  18. Thanks for sharing. This is a fantastic blog. Really thank you! Awesome.

  19. I like this subject and it will help me a lot with my homework. Thanks for helping.

  20. Bobby says:

    Great post, really enjoyed it!
    — Bobby

Leave a Reply

Your email address will not be published. Required fields are marked *