When radar LSALT is lower than grid/route LSALT
 

If the radar LSALT is lower than grid or route LSALT, is there a requirement for ATC to say "Radar lowest safe" at the end of an instruction when leaving the grid or route LSALT on descent?

eg - ABC descend 1,700 "radar lowest safe"

In New Zealand the phraseology used is "Radar Terrain", appended to the altitude instruction.

In Oz.
There is no requirement in MATS to say it.
There is no requirement or phraseology shown in AIP.
Some controllers add radar lowest safe to the altitude.
I work in Cairns App and it's normal ops to be assigning a level below MSA etc. I just assign the level and get asked about 4 times a year if the level is radar terrain.

A mixed bag going into Townsville! Sometimes they tell you "Radar lowest safe" and sometimes they don't.

In the pre-GPS moving map days it did get your attention when cleared to descend below LSALT when you knew there was a big lump of granite not too far away.

Dr :8

If in doubt, ask.
 

I've been vectored off flight planned track in IMC over elevated terrain and cleared to descend to A030, grid LSALT 3800. I simply read back the clearance and appended "Confirm, radar terrain cleared". The controller confirmed and away we went.

Quite often controllers will automatically include the term "radar terrain cleared" (or similar) with descent clearances, especially when the aircraft is over, or has just left, an area of high terrain in IMC or at night.

I think you will find in Townsville you are told 'Radar Lowest Safe' when that is the lowest radar step that they can assign you, I think they are hinting you to report visual. Often I will be told 'descent to XXX Radar Lowest Safe report when visual'. The whole point of the radar chart is to be more accurate than a grid LSALT or 25nm MSA, but if your worried...ask.

I reckon this is usually why it's added.

From my example above; They could hint all they like but that wasn't making the rain go away. 2000m vis 'til 3 miles from the field.

I have also been informed "radar terrain clear" while VMC at night and therefore no requirement to report visual, probably so I was less likely to ask if they just gave me a plain old descent clearance.

No need to hint!

I will call "visual" just as soon as I am, and believe that I will stay that way.

Dr :8

Information from a long time friend is that QLK generally do not call visual until they have been assigned the lowest possible step. 'Hint' was a poor choice of words for me to use..... What I meant was it is ATC's way of saying thats the lowest your gonna get report when you are visual.

Cheers

what would have happened here
 

What would the situation have been for the Air Asia flights that got too low coming into the Gold Coast last week?

Noticed this report earlier.

Serious AirAsiaX incidents at Gold Coast being investigated – Plane Talking

If I wanted the crew to report visual I would ask if they were visual. If they didnt call visual and I did not need it for sequencing then the aircraft would be processed for the IAL appropriate.

Controllers using surveillance based control (cant call it radar cause it is all digitally manipulated these days!) will assign the lowest available level on radar terrain appropriate for the flight segment being flown. If the level is not based on the RTC then it is the CTA steps or appended by the word visual once you have called visual.

Anything else is superfluous as AIP is reasonably clear (oxymoron I know) about what levels are assigned. However, if you are in doubt as to the level being assigned - ask, controllers are not fool proof (yet).

AirAsiaX
 

HOLY LSALT:eek:

I gather this was not a 100ft transponder tolerance matter????

So how many hundred feet are we talking?:uhoh:

If that was a red tail and a white roo.....the press would be going nuts.