Military Terrain Clearance

[Gerard M]

I have another question as google was unable to help me.
Was listening to the radio and heard the controller tell Trojan 27 to maintain 3*00ft, military terrain clearance, etc etc.

What is the difference between this clearance and i guess maintaining a normal 3000ft altitude?

Cheers
Gerard


And yes i just realized there is a typo in the title, so mods feel free to fix it please.

[NickN]

It wasn't minimum terrain clearance that they said?

[Mick.B]

Never heard that one before.

[Daniel G]

Out of curiosity, what were they doing? Were they being vectored around?

[Gerard M]

From what Nick said i'm second guessing what i heard now although he did repeat it twice so i thought i heard military. From the sounds of it he was heading towards Richmond to complete some sort of op as there was three odd requests from the controller whether he wanted to continue with his ops despite the weather. They were out west for a while and then were coming into i think the Richmond training area?

Does maintain minimum terrain clearance fit better than military?

[Drew H]

I've definitely heard it used for hercs before too, so I don't think you misheard, Gerard.

[Daniel G]

Interesting! I believe the military use a different type of navigational chart? Different set of rules also. Always very cautious flying into places such as Willy or Townsville and interpreting the clearances they deliver, particularly at night into Williamtown!

[Nicholas Togias]

"descend to 2000, military terrain clearance" is the same as the civilian world using the phrase "descend to 2000, VISUAL".

When this clearance is given the pilot is accepting responsibility for terrain avoidance below the minimum altitudes for terrain clearance in IMC (MVA, MSA, LSALT).

[Daniel G]

Ah, I assumed that this scenario was at night, going off the time of the post. Also Nick, you can only descend 'visual' if you are in fact visual - not in IMC. ;)

[Nicholas Togias]

yes, apologies, for descending visual I understand you have to have reported visual, but in regards to "military terrain clearance" a military pilot can descend below LSALT in IMC as long as "military terrain clearance" is given in conjuction with the descent instruction.

"descend to 2000, military terrain clearance" is the same as the civilian world using the phrase "descend to 2000, VISUAL".

SO - I guess its not the same thing

[Gerard M]

Cheers Nicholas, much appreciated.

Can anyone enlighten me as to what the tack hand runway 10 approach? (for Richmond).

[Craig Murray]

tack hand runway 10 approach?

"Tack Hand" translates correctly as TACAN (Tactical Aerial Navigation) which is a system used by the military since forever.

More info can be found here:

TACAN at Wiki - Wiki is never wrong! (http://en.wikipedia.org/wiki/Tactical_Air_Navigation)

[Daniel G]

a military pilot can descend below LSALT in IMC as long as "military terrain clearance" is given in conjuction with the descent instruction.


What method do they then use to ensure terrain clearance?

[Nicholas Togias]

well they still use a LSALT, just a military terain clearance is lower than a civilian LSALT

[Gerard M]

Cheers Craig. I'l have to disagree on wiki being never wrong though...it doesn't look to good when it pops up in an essay reference list :p but it did answer my question.

[Gerard M]

Just heard another approach that i wouldn't have minded going to see.

Mentor 09 (A97-448), Cleared Visual approach, full-stop Runway 28, descend to 1500ft from FL150 at pilots discretion, maintain Military Terrain Clearance. Requesting NVG APPROACH, lights out please.:p

Can't say i have ever been at Richmond at night to see a Hurc come in without the runway lights using just night vision. Would make for a good shot from the end of the runway.

And actually this is the first time i have heard them request lights out and a NVG approach. And i just presume that this approach coupled with the request for lights out means night vision.

[damien b]

You wouldn't see much Gerard. The aircraft (a J model) would have had all nav lights turned off with only the NVG compatable landing lights in use, which you wouldn't see. As for taking a photo - not much to see either, just a dark hulk flying overhead.

As a former techo who used to work on the C-130's, especially on a real dark night the first clue that you had sometimes that an aircraft had arrived that you were waiting to marshall in was the sound of the engines going into reverse after touchdown.

Its a procedure they use to practice at night in winter all the time and with a full (almost full) moon and clear night, its a good time to fly NVG.

[Gerard M]

I didn't realize that they turn off all the lights on their aircraft too. Makes sense though when you think about it. Thanks Damien.