SALR
 

anyone help,have my cpl(h) and while studying for it i was told that the SALR in met was 1.8 degrees per 1000 ft. Getting a ppl ground course ready i obtained a cd of met, and they are saying its 1.5 degrees per 1000 ft. can anyone enlighten me. thanks

r22-Male,

I hope i remember this correctly, its been a long time since i sat my Cpl exams,

The SALR (WET AIR) is 1.5 per 1000 ft
The DALR (DRY AIR) is 3.0 per 1000 ft
The ELR Standard ISA is 2.0 per 1000ft or to be precise 1.98 C/1000ft

Hopes this helps

CVR

If I'm wrong i do apologise:ugh:

That is correct. These figures are used in Australian CPL exams, including IREX.

Not sure about ATPL though.

Yep, same in the ATPL met.

HP

I have to say it--I have NEVER found a need to use these figures once during my aviation career---I'm glad everyone is learning them.........
Has anyone in the rotary world ever had a use for them?

well i've not actually started my career - but isnt it the base of the rule of thumb that the cloudbase should be about 400 multiplied by the difference between temperature and dew point?

Ive got only vague memories (worrying since I sat met 3 months ago!), but its 400 feet (ie 1000 / 2.5) because the SALR is actually a curve not linear, so 2.5 is a better estimation that 3.

Of course I could be talking rubbish!

The SALR can range from 4°C to as high as 9°C per 1000 m, but the average for JAA exam purposes (for lower levels anyway) is 6°C per 1000 m, or 1.8°C per 1000 feet (it's clearly written in the learning objectives).

And Gordy - if you want to make best use of your performance charts in mountains, lapse rates are very useful.

Phil

I knew I'd take a hit on that comment---like you say, those numbers can vary, therefore, based upon my experience and my kind of operations, learning those numbers have had no practical use for me.
I will admit that they may be useful to some out there, but I am one of those who does not like to learn numbers for the sake of it. I prefer to understand the practical applications of weather.
If for no other reason, than some may learn something, or find it interesting--in terms of mountain flying, especially for fire and other utility work, here is an example of the weather reports I use:
Fire Weather
What is often not taught to students is that there are many other sources of weather that may be more pertinant to helicopter operations than aviation weather reports. Lets face face it---aviation weather reports are geared towards flying from A to B, rarely will you get a detailed "spot" forecast.

I hear you on aviation weather reports - it's got to the stage where I only look at them for legal reasons - of what use is a forecast that says "visibility will be 100 m in hill fog"? or "800 m in showers"? I want to know where the fog is! :)

I used to have a network of friends round the UK that I would ring up - much more efficient!

If I was running a company there again, I would have some of those creative britecams dotted around the country that you can access from the internet. I know there are some surf ones available in the West Country which are quite useful

Phil

Have to agree with you there---I use webcams all the time---even the road report websites have good cams on them---I can check I5 in California almost from LA to Oregon on webcams.
For all the "new kids on the block"---think outside the box---Avaition weather reports are not always the best.......

I am currently studying the ground school for CPL(H) (not ATPL) with a school in Coventry!

I have their Met file open in front of me just now and, large as life and twice as ugly, it hath writ, SALR = 1.5 deg C per 1,000 ft.

Paco, would there be a difference between the figures that a student would use for CPL exams and ATPL exams?

Cheers

Whirls

Mate,

I think the bottom line is this. Learn the book numbers for DALR and SALR, do (and pass) the test, and you're golden. This stuff is just general knowledge of the world we live (and fly) in...the meteorologists (or weather guessers as I like to call them) are the ones who use this data (DALR, SALR, and ELR) to determine what they THINK will happen today at your aerodrome and they then publish a 'weather guess' or, as some people call them, TAF's. Thats my take on this stuff.

All the best lads,

HP

Fully agree with Gordy and Helopat. It's all 'interesting' to know. Just pass the test and put it in the drawer with the other 80% of stuff to forget.

Gordy thanks for the Fire weather link, very interesting.

That's all very well but ... if the JAA exams are based on one rate and the books from which I'm studying have another rate, it could mean getting a question wrong which, in my case, could be the difference between pass and fail!!!! :}

When the questions are all multi-guess, there is no scope for error; if they were written, I would still get some credit for the right method even if the wrong rate were used.

Cheers

Whirls

SALR = saturated adiabatic lapse rate 1.5 CºC per 1000 ft.
ELR = environmental lapse rate 2ºC per 1000 ft. (ISA, standard lapse rate)

So SALR doesn't mean Standard Adiabatic Lapse Rate, maybe the confusion lies there.

I don't think anyone's mentioned Standard ALR; but two people have clearly mentioned that 1.8 deg/1,000 ft is used for JAA purposes.

The other thought is whether the 1.8 deg/1,000 ft is derived from "iffy" conversion and rounding factors from the 6 deg/1,000m as quoted by paco.

Obviously, I shall stick with 1.5 deg/1,000 'cos that's what I've learned but, if I get one of those questions wrong, then somebody will get duffed up behind the bike sheds; not sure who yet!!

Cheers

Whirls

Hmmmmm - RULE # 1.

RULE # 2.

I am positive that I remember it being 1.725 recurring over down under here Whirls!

Based on the usual standard of JAA questions I would think that the 1.8 degree figure is wrong! :) Certainly I was originally taught that it was 1.5.

Phil

SALR
 

I am studying ATPL (H) at BGS and the figure quoted in the manuals is 1.8 deg per 1000ft at sea level in temperate climates.:confused:

paco - are you just making sure it's not you whom I duff up behind the bike sheds?! :} :p

UKhelipilot22 - perhaps the tactic is to work out two answers to an SALR question; one using 1.5 and the other using 1.8 and see which answer is one of the choices. However, if they're both there - it's 50:50 innit?!

Cheers

Whirls