Local Mean Time (LMT) is not local time

[FGD135]

Local Mean Time (LMT) is not the same as "local time". The two are completely different things.


Everybody on the operational side of aviation should know this, but incredibly, I see pilots - even a Chief Pilot - using the term "LMT" when what they really mean is just plain old local time.


Even more incredible is the fact that ERSA seems to think the two are the same. On page INTRO-6 of ERSA, it says:


4.1 Time throughout this document is normally shown in UTC. Where local time is intended it will be followed by the abbreviation LMT (Local Mean Time).


There should be an "official" abbreviation for "local time". Something like "LT" would be just fine. Incredibly, there is no abbreviation for "local time" - which is probably why people are using "LMT".


Doh.

[CaptainMidnight]

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[jas24zzk]

in the voice of Elmer Fudd

'vewy intwesting'


trying to write this without confusing even myself, given I have spent time teaching this.....

The error in the ERSA definition seems to be lack of conformance with accepted terms.

Looking into the ERSA entry you have posted, leaves open the door to 2 different TIMES.

LMT (Local Mean Time) is a valid terminology and has meaning.
Local TIme. Has no definition in ICAO or any other structure.

Your final sentence is very correct and there is a a short for it. and thats LST (as taught at BAK,PPL and CPL level)

Local Time does not exist in the syllabus, but Local Mean Time and Local Standard Time do. both must be taught and understood.


I don't have a current ERSA handy, but if you can find an entry where they use the LMT abbreviation, post it for further analysis...let see what they are publishing


Cheers
Jas

[Blueskymine]

Is it that big a deal?

[jas24zzk]

In a flight planing situation where you might be pressed for end of daylight...yes it is.

[Blueskymine]

And I'm sure you'll be using naips which gives you last light far more accurately than you could calculate from airway manuals :)

[jas24zzk]

Fair point...my last response was a lil open ended.

EFB's aside.................


The regulator requires you to be exacting. Why should the regulators documentation be that ambiguous and open to that level of 'interpretation'????????????????


I agree with the OP the wording, if only acronyms should be correct and not open to interpretation....one that may be wrong!

[Trent 972]

OTOH
'Local Time' does get its own paragraph in the AIP in GEN 2.7 -2 (1.3). :)

'Local Time' also gets a mention on the illustrated 'Flight Note' - appendix 3 of AIP ENR1.10 - 29

and…. oddly enough it gets a burst in the very next dot point (4.2) after the example given in the op.

[FGD135]

I don't have a current ERSA handy, but if you can find an entry where they use the LMT abbreviation, post it for further analysis...let see what they are publishing


Here is an extract from the entry for PORTLAND:


HANDLING SERVICES AND FACILITIES
Portland Aero Club: AVGAS H24. V, MC. Phone 0417 163 324.
BP: JET A1 W 0600-1800 LMT, SAT 0900-1300 LMT, SUN 1400-1800 LMT, AH Callout fee applies.
Phone 03 5526 5201, AH 0427 360 578

[mcgrath50]

So Air BP in Hedland starts work at different times each day as the earth's rotation round the sun changes? I know people there are a bit different but I didn't realise they were Pagans! :E