732 holding speed (IFR diversion)
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Joined: Sep 2005
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From: NZWN New Zealand
732 holding speed (IFR diversion)
Hey gang, I'm not an ATPL but want to resolve a very difficult mission for a Boeing 737-200-9 from a very limited 4,490ft (1347m) runway flying 265nm. The divert airfield is en-route and almost directly under the track to final destination.
Distance from take off airport to divert field is 207nm.
According to ICAO Annex 6 (4.3.6.3) The 732 would need to lift off with fuel to reach destination+3% extra en route fuel, shoot two approaches, divert back to diversionary field (58nm) plus fuel for 30 mins at holding speed.
Question: For B737-200-9 arriving overhead destination at 37,045kg weight, what is a reasonable holding speed and what would fuel burn be for that holding speed at say 2,000ft ?
Question: Using dispatch techniques can total fuel reserves be reduced by redispatch at an en-route decision point in the air ?
For example soon after take off establishing if the final destination is open and if necessary deciding early to divert to the airport only 207nm away ?
I estimate the fuel required for the ICAO Annex 6 (4.3.6.3) plan are as follows : taxi 200kg; APU 60kg; En-route fuel 1650kg; IFR reserve 1875kg.
What I am asking is first of all have I over calculated the holding speed fuel (because I calculate that at normal 420 knot cruise) and secondly can the IFR reserve laefully be reduced to give better payload from originating runway ?
In anticipation of a drubbing thanks for your answers.
Distance from take off airport to divert field is 207nm.
According to ICAO Annex 6 (4.3.6.3) The 732 would need to lift off with fuel to reach destination+3% extra en route fuel, shoot two approaches, divert back to diversionary field (58nm) plus fuel for 30 mins at holding speed.
Question: For B737-200-9 arriving overhead destination at 37,045kg weight, what is a reasonable holding speed and what would fuel burn be for that holding speed at say 2,000ft ?
Question: Using dispatch techniques can total fuel reserves be reduced by redispatch at an en-route decision point in the air ?
For example soon after take off establishing if the final destination is open and if necessary deciding early to divert to the airport only 207nm away ?
I estimate the fuel required for the ICAO Annex 6 (4.3.6.3) plan are as follows : taxi 200kg; APU 60kg; En-route fuel 1650kg; IFR reserve 1875kg.
What I am asking is first of all have I over calculated the holding speed fuel (because I calculate that at normal 420 knot cruise) and secondly can the IFR reserve laefully be reduced to give better payload from originating runway ?
In anticipation of a drubbing thanks for your answers.
Joined: Nov 2006
Posts: 1
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From: NZWN
737-200 fuel planning
Kiwiguy...may not be able to give you the exact answer but did have 15 years flight planning 737-200 series aircraft for the major NZ carrier some years ago. Have dug into my personal aviation archives (don't ask why I kept these)....but may be able to fill in a few gaps.
At the time we planned to CAA rules (CASO 15) and not the annex for domestic flights. Initially we used flight planning tables but later on moved to a mainframe based system. Fuels below based on Pratt JT8D-15A.
Flight planning (assuming an alternate) consisted of
a) Pre-flight fuel (150kg - this gave 50kg for 30min of APU ops and 100kg for 5min start and taxi fuel)
b) departure fuel if required - calculated at 3min at 139kg if a 180 required after T/O
c) A-B fuel (this was from start of T/O to 1500ft overhead B)
d) 6% contigency fuel of A-B B/O
e) landing fuel - standard 135kg (3min)
f) instrument approach fuel - if straight in then 0 kg. If 'around the corner' 8min at 400kg, if straight in followed by missed approach and a second approach 15min at 770kg. if round the corner and a second go - 23min at 1170kg.
g) B-C diversion fuel
h) 3% contigency of B-C B/O
i) instrument approach fuel at C (as per 'f' above)
j) 30min holding fuel overhead alternate at 1500ft
k) where applicable a PDA allowance which was aircraft specific.
Holding speeds according to the book were 210kt clean. Don't forget the 250kt speed restriction below 10,000ft anyway. The tables I have indicated that at a ZFW of 38,000kgs then 30min hold equated to 1140kgs.
As a quick example I have an old computer fligt plan going NZWN-NZAA divert NZAA-NZHN which appears to be similar to your scenario. With a ZFW of 36300kgs at FL330 A-B calculated B/O was 44min at 1979kg (wind comp P010), B-C B/O was 17min at 887kg and alt reserve was 30min at 1146kg. Extra hold was based on 2400kg/hr.
I don't quite understand your inflight redispatch comment. You can divert to your alternate C on the way to B if you wish but this wouldn't affect your original planned fuel to go A-B. If you are planning A-C to reduce your fuel uplift that is a possibility but in the real world you might be embarrased if B suddenly opened. The other way you could get a bit more payload on departure is to use a higher flap setting eg flaps 5 or 15 instead of 1.
Cheers
At the time we planned to CAA rules (CASO 15) and not the annex for domestic flights. Initially we used flight planning tables but later on moved to a mainframe based system. Fuels below based on Pratt JT8D-15A.
Flight planning (assuming an alternate) consisted of
a) Pre-flight fuel (150kg - this gave 50kg for 30min of APU ops and 100kg for 5min start and taxi fuel)
b) departure fuel if required - calculated at 3min at 139kg if a 180 required after T/O
c) A-B fuel (this was from start of T/O to 1500ft overhead B)
d) 6% contigency fuel of A-B B/O
e) landing fuel - standard 135kg (3min)
f) instrument approach fuel - if straight in then 0 kg. If 'around the corner' 8min at 400kg, if straight in followed by missed approach and a second approach 15min at 770kg. if round the corner and a second go - 23min at 1170kg.
g) B-C diversion fuel
h) 3% contigency of B-C B/O
i) instrument approach fuel at C (as per 'f' above)
j) 30min holding fuel overhead alternate at 1500ft
k) where applicable a PDA allowance which was aircraft specific.
Holding speeds according to the book were 210kt clean. Don't forget the 250kt speed restriction below 10,000ft anyway. The tables I have indicated that at a ZFW of 38,000kgs then 30min hold equated to 1140kgs.
As a quick example I have an old computer fligt plan going NZWN-NZAA divert NZAA-NZHN which appears to be similar to your scenario. With a ZFW of 36300kgs at FL330 A-B calculated B/O was 44min at 1979kg (wind comp P010), B-C B/O was 17min at 887kg and alt reserve was 30min at 1146kg. Extra hold was based on 2400kg/hr.
I don't quite understand your inflight redispatch comment. You can divert to your alternate C on the way to B if you wish but this wouldn't affect your original planned fuel to go A-B. If you are planning A-C to reduce your fuel uplift that is a possibility but in the real world you might be embarrased if B suddenly opened. The other way you could get a bit more payload on departure is to use a higher flap setting eg flaps 5 or 15 instead of 1.
Cheers
Joined: Jul 2002
Posts: 71
Likes: 0
From: Somewhere between Cape Reinga and Invercargill
Hey gang, I'm not an ATPL but want to resolve a very difficult mission for a Boeing 737-200-9 from a very limited 4,490ft (1347m) runway flying 265nm. The divert airfield is en-route and almost directly under the track to final destination.
Distance from take off airport to divert field is 207nm.
According to ICAO Annex 6 (4.3.6.3) The 732 would need to lift off with fuel to reach destination+3% extra en route fuel, shoot two approaches, divert back to diversionary field (58nm) plus fuel for 30 mins at holding speed.
Question: For B737-200-9 arriving overhead destination at 37,045kg weight, what is a reasonable holding speed and what would fuel burn be for that holding speed at say 2,000ft ?
Question: Using dispatch techniques can total fuel reserves be reduced by redispatch at an en-route decision point in the air ?
For example soon after take off establishing if the final destination is open and if necessary deciding early to divert to the airport only 207nm away ?
I estimate the fuel required for the ICAO Annex 6 (4.3.6.3) plan are as follows : taxi 200kg; APU 60kg; En-route fuel 1650kg; IFR reserve 1875kg.
What I am asking is first of all have I over calculated the holding speed fuel (because I calculate that at normal 420 knot cruise) and secondly can the IFR reserve laefully be reduced to give better payload from originating runway ?
In anticipation of a drubbing thanks for your answers.
Distance from take off airport to divert field is 207nm.
According to ICAO Annex 6 (4.3.6.3) The 732 would need to lift off with fuel to reach destination+3% extra en route fuel, shoot two approaches, divert back to diversionary field (58nm) plus fuel for 30 mins at holding speed.
Question: For B737-200-9 arriving overhead destination at 37,045kg weight, what is a reasonable holding speed and what would fuel burn be for that holding speed at say 2,000ft ?
Question: Using dispatch techniques can total fuel reserves be reduced by redispatch at an en-route decision point in the air ?
For example soon after take off establishing if the final destination is open and if necessary deciding early to divert to the airport only 207nm away ?
I estimate the fuel required for the ICAO Annex 6 (4.3.6.3) plan are as follows : taxi 200kg; APU 60kg; En-route fuel 1650kg; IFR reserve 1875kg.
What I am asking is first of all have I over calculated the holding speed fuel (because I calculate that at normal 420 knot cruise) and secondly can the IFR reserve laefully be reduced to give better payload from originating runway ?
In anticipation of a drubbing thanks for your answers.
Cheers
James
