Downhill slope and Maximum mass for take-off

[manucordier]

Hi,

This is a performance question:

If the take-off mass of an aeroplane is tyre speed limited, downhill slope would:

Answer: has no effect on the maximum mass for take off (according to FlyAround).

Well, I would have said that with a downhill slope you will accelerate to V1 faster, thus reaching V1 in a smaller distance which should allow you to take-off with a higher weight than with a zero slope runway.

Moreover in case of engine failure before V1, you will have more runway to stop the aircraft (... I understand that because of the downslope you will need a greater distance to stop the airplane but you do have that greater distance because V1 was reached sooner).

Who can explain the FlyAround given answer ?

Thanks,
Emmanuel Cordier.

[Keith.Williams.]

Your statements that:

Well, I would have said that with a downhill slope you will accelerate to V1 faster, thus reaching V1 in a smaller distance which should allow you to take-off with a higher weight than with a zero slope runway.

Moreover in case of engine failure before V1, you will have more runway to stop the aircraft (... I understand that because of the downslope you will need a greater distance to stop the airplane but you do have that greater distance because V1 was reached sooner).

Are OK but they miss the point of the question.

The key piece of information in this question is that the aeroplane is tyre speed limited.

This means that to avoid bursting the tyre we must ensure the Vlof is not graeter than the tyre speed limit.

So the question now becomes "What affect will a donwslope or upslope have on Vlof?"

The answer is that runway slope will not affect Vlof so it will not affect the tyre speed limited take-off mass.

Now a question for you:

Would it not be better if you were to to use a QB which includes lots of detailed explanations?

[manucordier]

Well Thanks for your advice but I do not own such a QB ? Could you recommend one that I could find online ?

[Keith.Williams.]

I am the author of an interactive CD ROM version of the CQB, so I am not really the right person to give advice on which of the on-line versions is the best.

[manucordier]

Hi Keith,

I must say that I'd rather be looking for a free solution. The thing is that I've been studying this way for the last few months, I mean looking on the internet on many websites and reading a lot of online literature to find logic explanations to all the questions I had (I must say that I've been amazed by the very detailed information one can find on the internet about very technical things). When I was unable to find a clear answer I posted a message on pprune.org and I always got a very detailed answer from your part or from others.

This way of working gave me very good results at the first round of exams,... and I must say that I learned much more than by reading passively a book (which I have also done). However it consumes a lot of time.

Anyway, I might be interested by your stuff, where can I find more information about it ? How much does it cost and can I have a demo version before I buy it ?

Thanks Keith.

Have a good day,
Emmanuel.

[Dick Whittingham]

Greetings Emmanuel,

If you are sitting the ATPL Exams you will be training at a recognised FTO. Would you mind telling us which School it is?

Dick

[Keith.Williams.]

You can find the CD on the pooleys.co.uk website and on the transair.co.uk websites here in the UK. It is also on websites in other countries but I do not know which.

I am not trying to sell you anything here in PPRUNE. But you are clearly keen to learn and understand the subjects, rather than simply memorising answers. So if you send me a PM telling me the address to which I should send it, I will give you a free copy of the CD.

[manucordier]

Hi Dick,

I am training at Cuatro Vientos (LECU) Madrid - Spain, at AEROFAN FTO (http://www.aerofanfto.com/).

Very good quality/price ratio for PPL and ATPL however I recommend you to pay attention to a few things :

If your directional gyro is not working well during taxi (so do the taxi checks !!), cancel the flight, tell the reason to the office and ask them to fix it ! They will do so or they will offer you another aircraft.

The ability of the instructors to transmit their knowledge and skills is a bit uneven. Try to fly with different instructors and then stick with one you like. I can recommend you a few very good ones (PM).

I must say that generally the school is responsive to remarks. At least it has been in my case. So if you have something to say (positive or negative) say it and don't wait. They will help you and they will offer you a solution.

Also the briefings and debriefings are good but quick. So study well at home and train your IFR with a flight simulator because you won't have time to ask many questions. I use this Java IFR simulator online (good and easy to use) : Intsrument flight : IFR flight simulator - freeware (IR: Instrument Rating) (http://cours-de-math.eu/ifr-training/instrument-flight-simulator.php)

Cuatro vientos airport is very busy so if your flight is planned at 9h AM be on time and do what you have to do very quickly. If you call the tower for taxi after 09h05 you'll have to wait your turn to taxi up to 45 minutes with the engine running (about 300 euros if you are flying the twin).

Last remark : the instructor is sometimes trying to do the radiocommunication work for you. This is very comfortable but don't let him do that. Listen to what he says during the first flight and then on the next flight try to talk before he does !

Good day.


Emmanuel.

[vfrrider481]

Manucordier,

A little advice is be careful with the "free" online question banks. Many of them are poor quality translations where the inaccurate translation causes more confusion.

Again, the free ones tend not to be updated or the most current, causing more problems.

As Keith has said the free ones also have little if any explanation of the answers or reasoning and generally don't have a support forum.

Being polite as I can, given that CPL/IR training costs tens of thousands why skimp on a couple of hundred? Risking a fail on the exams through trying to save a couple of hundred pounds seems like false economy to me.

Regards,

V