Simviation Forum - First true "Cross country" flight

Aug 26^th, 2008 at 9:28am

Wingo Offline
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G'day all,

I'm currently preparing for my first true cross country flight departing at 08272000 (6 am local time). The flight is from Moorabbin Airport, which is to the south east of Melbourne, to Bankstown Airport west of Sydney. Total flight time is expected to be around 4 hours, covering a distance of about 400nm.

What I need help with is deciding whether I should land and refuel enroute or not. I've crunched the numbers out using a standard fuel flow of 36 litres per hour. Best case scenario (20 knot tail wind for every leg) will see me arrive with 48 litres margin fuel (excluding reserves). Assuming worst case (20 knots head wind for every leg) I will arrive over head the aerodrome and just enter into my reserves. Assuming most likely for this time of year, a quartering tail wind, I should arrive with about 10-20 litres of margin fuel.

As most would understand, 36 litres per hour is quite conservative and if the aircraft is leaned it will only use 30-32 litres per hour. I would prefer not to land and just go direct, but I also want to be on the safe side.

I ask those which have more experience than I, with these numbers in which cases would you plan a fuel stop?

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Reply #1 - Aug 26^th, 2008 at 9:51am

Brett_Henderson Offline
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I try to be my over-the-top, on the safety side of fuel planning. I've been in a plane where an unexpected headwind put me WELL into reserves.

IT AINT FUN

Now.. I've also got a buit-in safety device (my bladder is only good for 2.5 hours of flying at a time), so I'm rarely pushing the limit.

ANYWAY (using non-metric volumes)( 40 gals available.. 9GPH).. a C172 has a 4 hour duration with full tanks (that leaves just about 1/2 hour of VFR reserve)

If your bladder can take it.. I'd PLAN for for no fueling,, but MAKE SURE it's a viable option. I know that's obvious advice, but it's the only real answer to your question.

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Reply #2 - Aug 26^th, 2008 at 10:08am

Wingo Offline
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Thanks Brett. I understand what you're saying, I'll assess the forecast winds on the day and make my decision on that knowing that I'll most likely be able to do a non-stop. In the aircraft I'll keep on top of my ground speed, time intervals and fuel consumption. My planned refuelling point is an aerodrome I'll be overflying enroute, so if things aren't going as expected I can always drop in for a drop.

On the other note, my bladder doesn't pose a problem. It could easily outlast the endurance of a 172 Tongue

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Reply #3 - Aug 26^th, 2008 at 11:05am

beaky Offline
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Two general rules of thumb:
1) An hour reserve for VFR is wise.
2) If the trip is a RT with the return on the same day, forget any benefit from a tailwind on the way out. Grin

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Reply #4 - Aug 26^th, 2008 at 11:24am

Brett_Henderson Offline
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Quote:

1) An hour reserve for VFR is wise.

That's the truth, brother. Get into that hour and you'll get to see the minute-hand on your watch move like a sweep, second-hand..

Shocked

Quote:

2) If the trip is a RT with the return on the same day, forget any benefit from a tailwind on the way out

More infinite sage-dom.. A tailwind does NOT offset the headwind on a round trip.. Do the math..

400nm round-trip @ 100kias, no wind =

4.00 hours

Add wind (even a perfect head/tail-wind)

200nm leg @ 100ktas + 20knot tailwind = 1.67 hours

200nm leg @ 100ktas - 20knot headwind = 2.50 hours
---------------------------------------------------------------

4.17 hours

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Reply #5 - Aug 26^th, 2008 at 10:36pm

Wingo Offline
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Your marmalade is no match
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YSBK. Back where I belong.

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Using today's winds (which should be similar to tomorrows) I'll be arriving with a 39 litre margin on top of my 45 minute reserve, so that should give me nearly 2 hours in the tank on landing.

It isn't going to be a round trip, just a one way with the return flight on Tuesday. I'm going to assume I'll have to land and refuel on the way down due to a likely headwind.

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Reply #6 - Aug 26^th, 2008 at 10:45pm

beaky Offline
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Wingo wrote on Aug 26^th, 2008 at 10:36pm:

Using today's winds (which should be similar to tomorrows) I'll be arriving with a 39 litre margin on top of my 45 minute reserve, so that should give me nearly 2 hours in the tank on landing.

It isn't going to be a round trip, just a one way with the return flight on Tuesday. I'm going to assume I'll have to land and refuel on the way down due to a likely headwind.

That's not exactly conservative (be sure to check your groundspeed ASAP after leveling off; yesterday's winds may be of no use at that point), but it should work out well enough.

If I were you, though, I'd plan on a possible stop halfway or thereabouts... after 2 hrs you may need a break, or wind or weather may force your hand.

I flew a 4-hr leg in a Skyhawk once; it was plenty long enough. My fuel planning worked out just right, but it easily could have gone sour.

In any case, it's better to have that Plan B prepared rather than have to whip it up while in flight.
When you approach that field, decide then whether or not you want to stop there.
good luck, and have fun!!

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Reply #7 - Aug 29^th, 2008 at 11:02pm

Wingo Offline
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Your marmalade is no match
for my VEGEMITE!!
YSBK. Back where I belong.

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The flight went well and I didn't need to put plan B into use. Once levelled off and leaned I was burning about 24 litres per hour with a ground speed averaging 113 knots. I landed with about 80 litres left on board

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Reply #8 - Sep 14^th, 2008 at 2:23pm

SkyDreamer Offline
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When flying a cross country I always keep fuel my fuel above half tanks in case of a delay or I get send into a hold for a couple of hours gawd forbid if my aircraft burns 10.9 gallons per hour I will caculate it at 13 gallons in case I catch a really bad headwind my numbers give me room for reserve I would plan a stop when tanks get below half

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Reply #9 - Sep 15^th, 2008 at 6:20pm

Brett_Henderson Offline
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SkyDreamer wrote on Sep 14^th, 2008 at 2:23pm:

When flying a cross country I always keep fuel my fuel above half tanks in case of a delay or I get send into a hold for a couple of hours gawd forbid if my aircraft burns 10.9 gallons per hour I will caculate it at 13 gallons in case I catch a really bad headwind my numbers give me room for reserve I would plan a stop when tanks get below half

You can never fault someone for erring on the safe side... or in other words.. it's impossible to be too safe..

Realistically of course, that's not the case. The numbers you use here denote a light, piston single. And I'll assume we're still takling about VFR flying. The chances of being asked to hold while flying VFR are very VERY remote.. and the only viable circumstance I can think of, is that you insisted on landing at a crowded airport and would CHOOSE to circle around for a couple of hours.. Cheesy

Also.. as far as 1/2 tank reserves go.. If you take off with a couple of passengers and their bags.. 1/2 tank may be your starting fuel load.. Cool

AND.. if you're talking IFR.. your filed flight plan (it includes fuel on board) would be taken into consideration before ATC would be asking you to hold.

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Reply #10 - Sep 16^th, 2008 at 7:37pm

SkyDreamer Offline
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I was flying a Cessna 172RG I think over Arkansas I came into a airport there Fort Smith Regional the military took over the place airplane after airplane I was VFR and holded for 15-30 minutes while they sorted the military out never say never

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Reply #11 - Sep 16^th, 2008 at 8:44pm

Brett_Henderson Offline
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EVERY OUTER MARKER SHOULD
BE AN NDB

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SkyDreamer wrote on Sep 16^th, 2008 at 7:37pm:

I was flying a Cessna 172RG I think over Arkansas I came into a airport there Fort Smith Regional the military took over the place airplane after airplane I was VFR and holded for 15-30 minutes while they sorted the military out never say never

OK.. there's a learning experience here, for us all.

Can you be more specific ? Was that your intended destination ? Were you using flight-following ? Was there a NOTAM or any type of TFR ? When did this happen ?

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Reply #12 - Sep 16^th, 2008 at 9:28pm

SkyDreamer Offline
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This was back in 2006 I was doing Traffic Pattern work I had done Three touch and go's I was gonna fly for about a hour or more but then the controller started taking alot I never heard military talk I guess because they were on TACAN channel all the sudden the Tower Controller told me Cessna 514 proceed downtown fort smith and hold which basically I got booted out of the pattern but I still did the Holding Pattern

There were no NOTAMS for the event or TFR's it just showes always take more than the VFR requirements which are 30 min day I always carry at least one hour of reserves

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