Hi

Passage over NDB ...needle reciprocates (ie turns 180 degrees)

Fuel: (150 + 30) x 1.15 + 45 = 252 minutes = 4.2 hours
4.2 x 120 = 504 litres + 15 taxi = 519 litres

[b]CORRECTION:[/b] after Richard's bit .... tried too quickly, didn't read all the info

My shot at it ...

David

Hi Dan,

The first problem refers to a fixed card ADF. In that case the needle will swing from the North position 360 [sup]o[/sup] (straight ahead) round to South 180 [sup]o[/sup] assuming no wind. It wouldn't matter which way you approached the NDB, the needle will always swing from "the nose" round to "the tail" as you fly over the top.

As for your other question, I don't know what other answer options were available but this is how I would work out the fuel required:

Fuel at start-up = (Fuel to dest + fuel to alternate) x 1.15 + fixed reserve + taxi allowance
= (150 minutes @ 120L/hr + 30 minutes @ 120L/hr) x 1.15 + 45 minutes @ 120 L/hr + 15 L
= (150x120/60 + 30x120/60) x 1.15 + 45x120/60 + 15
= 360 x 1.15 + 90 + 15
= 519 litres will be required in the tanks at start-up.

This assumes you need to apply the 15% variable reserve which, as you know, applies to all commercial flights. It also assumes the question wants the fuel at start-up. If the question wants the fuel at take-off, ignore the start-up and taxi allowance of 15L since that will have been burnt off by the time you line up for take-off.

Remember, the variable reserve applies to the flight fuel to the destination as well as the flight fuel to get to the alternate. You therefore calculate the variable reserve by multiplying the total flight fuel required by 1.15. The fixed reserve is simply 45 minutes at 120L per hour.

Cheers,

Rich

Hi Richard

Saw my error ... have corrected it ... should read the question ...

Regards
David

No worries - glad you got the same answer. Are you still up late studying, David? Good luck with your exam! It's tomorrow isn't it?

Yep ..... I really like the topic ... very interesting and useful.
I'm doing it just for the challenge.

[b]I put a post up earlier re a couple of questions I had 'issues' with from the Cybe Exams ... can you please clarify any of that for me ..[/b]

As an educator for some 39 years now, and having done all the CPL exams, I find the CASA examination not a real challenge on skills, knowledge and understanding ... more about 'other things' .. no need to expand on that, I think that has been flogged to death ... but no change from CASA ...

Oh well ...

Regards
David

Hi guys,

Another one that's got me stumped!

A vfr charter flight is planned from alpha 2904S 14722E to bravo 3213S 14833E on July 10.

Total flight time is 2hr 10 mins

The latest ETD Aplha in UTC is -

A)0731
B)0521
C)0741
D)0531

Somehow I came up with 0623z I'm lost what on earth am I doing wrong?

Thanks guys!

-Dan Parker

Also thanks to Richard and David for helping out on that, to clarify... Flight fuel variable reserve needs to be multiplied for total fuel then add reserve and taxi if needed? Or add total flight fuel fixed reserve then multiply and then add taxi fuel?

Hi Dan,

Variable reserve applies to flight fuel and flight fuel is the fuel you need to get to your destination and eventually on to your alternate. So, yes, you multiply the flight fuel total by 1.15 to get the flight fuel plus variable reserve.

To that amount you add your fixed reserve which is either specified as a certain quantity of fuel or a period of reserve at a specified fuel flow. On top of that you then add your start-up and taxi allowance and any holding fuel you need.

Here's the workflow:

[code] Flight fuel .....
+ Alternate fuel .....
-----------------------
apply 15% Variable ..... (multiply total above by 1.15)
+ fixed reserve .....
+ holding fuel .....
+ taxi/start-up .....
========================
TOTAL FUEL REQUIRED ....[/code]

Remember, variable reserve is not required on private flights according to CAAP 234.

As for the question on latest departure time, you need to arrive 10 minutes before last light. So, to solve the problem try this:

1) find EOD at Bravo using the EOD chart in the AIP.
2) Take 10 minutes off this time to get your latest permitted ETA at Bravo.
3) Convert that to UTC using the arc to time table in the AIP
4) Subtract 2hr 10 minute from this to get the latest departure time from Alpha in UTC.

If the question had wanted the latest departure time at Alpha, you would then convert the UTC answer to Alpha's local time using the Arc to Time table.

The trick with time questions is to ensure you are always working with the same time zone, usually UTC. Have another go, post your working and we'll take another look at it if you want.

Cheers,

Rich

EDIT: Corrected flight time to read 2hr 10 minutes.

Check EOD at Bravo on July 10. [1735 LMT]
Convert to UTC [subtract 9 hrs 53 min [0741]
Subtract 10 mins as per AIP ENR 1.2 para 1.1.2 Answer = 0731 UTC.
Subtract 2 hrs 10 mins = 0521 UTC.

Hi guys,

I really appreciate the help you've all given me!

Another query I have regarding fuel, let's say for example I was trying to find the fuel available for a flight, from what I understand you would take the total flight fuel in tanks then subtract the reserve and taxi and holding fuel then divide by 1.15 to get the reserve.

Why is it that when finding the fuel required I follow a system like this

Flight fuel + holding fuel x 1.15
+fixed reserve
+taxi reserve

But when finding the flight fuel available Shouldn't I reverse the system used above? Like this
Total fuel
Flight fuel - holding fuel / 1.15
- fixed reserve
- taxi reserve

In the book is says I should do this

Total fuel
- flight fuel
-holding fuel
- fixed reserve
- taxi fuel
Then divide by 1.15....

If anyone can clear this up for me it would be great!

Thanks alot guys

-Dan Parker

Dan

The variable reserve applies only to the actual flight fuel and the fuel to the alternate [if required]. You do not apply the 15% variable reserve to the holding, fixed reserve or taxi fuel. Therefore to find the total fuel required you do this:

Fuel required = flight fuel + alternate fuel [if required] x 1.15. That looks after the variable reserve. Then add the fixed reserve, holding [if required] and taxi.

To go the other way and find the flight fuel available you do this:
Flight fuel available = Total fuel at start-up - taxi - fixed reserve - holding. That takes care of everything except the variable reserve. So you then divide the remainder by 1.15 and that removes the variable reserve leaving the flight fuel available.

In your worked example you are including the holding fuel as thought it was flight fuel. That is not correct.

Thanks Bob that really seems easy when you break it down like that for me really appreciate the help!

Cheers

-Dan Parker