Hi,I was wondering how to calculate equitimepoint(s)For example: KLAX to PHNL then wat is the ETP point for that route???And is an ETP based on windforecast or just on NM???Thanks,

Hi,Well it depends on the ETOPS performance you are allowed, but it's very likely you would need an ETOPS 180 to run a twin engine plane between KLAX and PHNL. So you should be a maximum of 3hrs away from the nearest airport, which would be about 1200Nm from the nearest airport (that's based on a 400kts speed, which seems).I don't think the calculation is just taking into account the time flown at cruise level, but it also takes into account the depressurisation scenario, where you would fly at FL100, where you burn far more fuel than at cruise level.Hope this helps,Francois

Not sure, i think they are calculated by the equidistanceline intersecting the route. I can't imagine how one would try using wind forecasts to get an average GS and thus an 'equitime' point... must be very hard to calculate. For what i've seen, it's 2 distance circles, an equidistance line and the intersectionpoint.To calculate the exact point is not very easy. I once did it in Ilan's wonderfull fuel planner exel file(i added my own ETOPS section) in which I would firstly plote route, then for each consecutive pair of waypoints set up an equation, using 0

G-day,well at my airline ETP points are calulated by computer, (thank god)but if in flight you needed to calulate another ETP pairing you could use this formula:(Total Distance x groundspeed Back) Divided By (Groundspeed Back + On)The TAS and flight level to be used in these calculations are: (again at my airline)# ETP 1 Engine inoperative(ETP1) = 415 kts at FL180# ETP 1 Engine inoperative/Depressurised (ETP1D) = 370 kts at 10000ftThe appropriate TAS/Flight level and wind component will give you the Groundspeed Back / On. As a general rule, ETP1D requires more fuelLooking at a flight from KLAX to PHNL, there are no airports enroute that could be used for a ETP pairing. So, under 180min ETOPS you could use KLAX-PHNL or KLAX-PHOG pairings to calculate your required fuel for the flight.Remember the fuel required for a flight is the greater of 1 or 2:1. Departure to Destination (A-:( 10kg per nm for quick calculation Instrument Approach at Destination (800kg) Contingency Fuel (2% of A-:( Destination to alternate (B-C)10kg per nm for quick calculation Missed approach from destination (390kg) Visual Approach at Alternate (300kg) Alternate Reserve fuel-30mins holding at 1500ft (1900kg about) OR2. Fuel from A to ETP1D point plus 2% (10kg per nm) Fuel from ETP1D to emergy airoprt plus 5% (15kg per nm) APU fuel use from ETP1D to emergy airport (90kg per hr) Approach and missed approach at emergy airport (1190kg) Visual approach at emergy airport (300kg) 15 mins holding fuel at 1500ft (800kg about)On the KLAX to PHNL flight you would only have 1 ETP1D pairing, but on a flight, say NZAA to WSSS you would have about 4 different ETP1D pairingsHope this helps. Let me know if you want me to go into it alittle more (What we look at during preflight and inflight)Cheers cd

Many thanks Gents,I will check those things out you all said.PS. I have PACIFIC PLOTTING CHARTS which makes it easier to work with. www.simw.com

Roa,You always may go further in to detail if you want. :( ;)

Great explanation, just one question: What is meant by goundspeed back + on?ThanksB

B,GS ON = Ground speed to Destination or Airport in front (PHNL)GS BACK = Ground speed back to departure or rearward airport. (KLAX)The quickest way to find your ETP1D point on your flight plan airway (if you have a chart, is):# Fold the chart so your two ETOPS airports touch(one on top of the other), and crease the map.# Where the the crease crosses the airway you are flying is your "still" air ETP point (no wind factored in)Remember if you are certifed for 180 min ETOPS, your choosen airport pairings must be within 180 mins flight time at your "still air 1 engine inoperative speed". For my airline we use TAS 415KTS. This means 180 mins = 1245nm. (Flying 180mins at 415kts you will cover 1245nm)So what does this means... Range circles: (180 ETOPS)You must always plan to fly within 180min of your ETOPS airport. So if you draw 1245nm range circles around your ETOPS airports each circle should touch each other. Example. A flight from NTAA (Tahiti) to KLAXAgain for this flight you must stay within 1245nm of a airport.(180min ETOPS)If you draw 1245nm range circles around NTAA and KLAX you would soon realise that these range circles do not touch. You need a ETOPS airport (range circle)some where enroute to join up with the NTAA/KLAX circles. You could use PHNL.So your ETOPS pairings would be:NTAA-ETP1D-PHNLPHNL-ETP1D-KLAXYour job as a pilot is to make sure you remain within 1245nm of a ETOPS airport which is suitabile to use if needed. (Weather remains at or above landing minima and has sufficient faclities to safely accomplish a landing)Cheers cd

Roa,It's very interesting but I was wondering one thing.Which airline do you fly??? ;)

I couldn't edit anymore so here is another question.TOTAL DISTANCE....wat do you mean with that???TOTAL DISTANCE with wind corrections or without wind corrections???

G-day, Lets just say a south pacific airline in NZ.TOTAL DISTANCE = depart to destination (no wind factored in)Example: Flight from YSSY to NZAA.Total Distance = 1165 nmETP1 (1 engine inoperative) TAS = 415ktNormal flight planned 2 engine TAS = 447ktWind component on = +16ktWind component back = -30ktusing the formula;(1165 x 385) / 816 = 550nmSo your ETP1 point is 550nm from YSSYYou have to modify the formula if you are using ETOPS airports that are not on your flight planned route. (like using phnl in my other reply)Sorry i couldn't tell you what it is either??? Try and get your hands on a chart and calculate the ETP1's that way.

Thank you very much Roa!!! :)You been a very good help in the calculation of ETP's.But I still had two (last) questions:-When do you know wat kind of ETP you have to use?? Ie. # ETP 1 Engine inoperative(ETP1) = 415 kts at FL180 # ETP 1 Engine inoperative/Depressurised (ETP1D) = 370 kts at 10000ft-Is the wind component the average route head/tail wind or is it something else????