Terrain Clearance
Thread Starter
Terrain Clearance
There's been much in recent posts about terrain clearance on approach what about on departure.
Another thread in ATC issues gets the ball rolling. Just wouldn't mind some opinions from pilots here in OZ
I am currently having discussions here in OZ about terrain clearance on departure in a non-radar environment.
My understanding is that the pilot will:-
Set course at or above the LSALT for the route segment within 5 miles of the departure earodrome
My question is:- if/can ATC clear the aircraft to track initially on a diversion track (to facilitate separation with other traffic) then what is the LSALT for that diversion track (not being a published route) and what are the responsibilities for the pilot and/or ATC to ensure terrain clearance?
Another thread in ATC issues gets the ball rolling. Just wouldn't mind some opinions from pilots here in OZ
I am currently having discussions here in OZ about terrain clearance on departure in a non-radar environment.
My understanding is that the pilot will:-
Set course at or above the LSALT for the route segment within 5 miles of the departure earodrome
My question is:- if/can ATC clear the aircraft to track initially on a diversion track (to facilitate separation with other traffic) then what is the LSALT for that diversion track (not being a published route) and what are the responsibilities for the pilot and/or ATC to ensure terrain clearance?
IMO, ATC have no responsibility to provdie you with terrain clearance.
My understanding is: depending on what type of aircraft you are in, the CAO 20.7 series will give you the minimum obstacle clearance required until you reach the cruise eg 35ft above obstacles (50ft if you have to turn) at the performance required eg 2% net with an engine out. If all that's too hard, then you demand a departure from the overhead (or some other direction) to allow youself enough time and track miles to climb up to the appropriate MSA.
Therefore, no need to be at LSALT by 5nm, you only need to be missing the obstacles by 35ft (and tell the GPWS beforehand so it doesn't get excited).
My understanding is: depending on what type of aircraft you are in, the CAO 20.7 series will give you the minimum obstacle clearance required until you reach the cruise eg 35ft above obstacles (50ft if you have to turn) at the performance required eg 2% net with an engine out. If all that's too hard, then you demand a departure from the overhead (or some other direction) to allow youself enough time and track miles to climb up to the appropriate MSA.
Therefore, no need to be at LSALT by 5nm, you only need to be missing the obstacles by 35ft (and tell the GPWS beforehand so it doesn't get excited).
There is NO LEGAL requirement to be established on track by 5 nm.
There is a statement in AIP that you should BUT that passage has no legal basis in the requlations (i.e. no head of power) and is therefore a recommendation not a requirement.
It is however the PIC's responsibility to ensure that thay position the aircraft clear of terrain - in IMC on some arbitrary route it is nearly impossible.
You need a clear plan of where you are prepared to go if you enter cloud below the LSA and if ATC tell you go to somewhere else don't accept it - after all you are the one who is going to be first on the scene of the accident if you do fly into rising terrain in IMC!
There is a statement in AIP that you should BUT that passage has no legal basis in the requlations (i.e. no head of power) and is therefore a recommendation not a requirement.
It is however the PIC's responsibility to ensure that thay position the aircraft clear of terrain - in IMC on some arbitrary route it is nearly impossible.
You need a clear plan of where you are prepared to go if you enter cloud below the LSA and if ATC tell you go to somewhere else don't accept it - after all you are the one who is going to be first on the scene of the accident if you do fly into rising terrain in IMC!
Moderator
.. keep in mind that the the 35ft thing is clearance for the net flight path. Except for very close in obstacles, the aircraft OEI will be substantially higher that this ...
As a pilot, radar environment or not we have to ensure terrain clearance is met.
In aircraft above 5700 Kg, i.e. where 20.7.1B is applicable, for normal departures (all engines operating) we can follow SID's to accomplish that, even at non radar ports. (they have the gradient req'd available)
If no SID is available then ensuring you can guarantee obstacle clearance such as the circling altitude, then the 10 nm MSA (if there is one) the 25 nm MSA or the lowest safe which ever may be lower, prior to transition ing to the next, you have achieved the required goal.
e.g. circling alt is 950 msa is 2000ft , 25 msa 3400ft, AND lsalt 5500ft.
With these numbers we have to achieve (cat C) 2000 ft by 4.2 nm, then 3400 ft by 10 nm and 5500 ft by 25 nm.
Apart from the circling altitude, the rest give you 1000ft obstacle clearance.
In all aircraft I have flown above 5700 kg, these restrictions are easily met.
If how ever we have an engine out situation, there is normally an engine out procedure we follow that is produced by the company. We would simply advise ATC of our intentions, i.e. we have had an engine failure and are maintaining rwy hdg, or turning right tracking ............
From my experience this is only relevant for aircraft above 5700 kgs. Below it seems to be brief your self prior to take off with no real knowledge of where the obstacles are (except the mark one eye balls) and good luck. this is based on the fact that airctaft below 5700 have no guaranteed climb performance.
I know some companies use performabce criteria above their's. i.e. use cat D for a cat C aircraft. I can only find one paragraph in AIP that suggests that that is not permitted. It makes alot of sense to me that we should be able to use it. Does any body have a reference that indicates this is allowed.
In aircraft above 5700 Kg, i.e. where 20.7.1B is applicable, for normal departures (all engines operating) we can follow SID's to accomplish that, even at non radar ports. (they have the gradient req'd available)
If no SID is available then ensuring you can guarantee obstacle clearance such as the circling altitude, then the 10 nm MSA (if there is one) the 25 nm MSA or the lowest safe which ever may be lower, prior to transition ing to the next, you have achieved the required goal.
e.g. circling alt is 950 msa is 2000ft , 25 msa 3400ft, AND lsalt 5500ft.
With these numbers we have to achieve (cat C) 2000 ft by 4.2 nm, then 3400 ft by 10 nm and 5500 ft by 25 nm.
Apart from the circling altitude, the rest give you 1000ft obstacle clearance.
In all aircraft I have flown above 5700 kg, these restrictions are easily met.
If how ever we have an engine out situation, there is normally an engine out procedure we follow that is produced by the company. We would simply advise ATC of our intentions, i.e. we have had an engine failure and are maintaining rwy hdg, or turning right tracking ............
From my experience this is only relevant for aircraft above 5700 kgs. Below it seems to be brief your self prior to take off with no real knowledge of where the obstacles are (except the mark one eye balls) and good luck. this is based on the fact that airctaft below 5700 have no guaranteed climb performance.
I know some companies use performabce criteria above their's. i.e. use cat D for a cat C aircraft. I can only find one paragraph in AIP that suggests that that is not permitted. It makes alot of sense to me that we should be able to use it. Does any body have a reference that indicates this is allowed.
Last edited by RENURPP; 29th Oct 2005 at 22:36.
ENR 1.1-11
Obstacle/terrain avoidance while below the LSALT or MSA, as applicable, is a pilot responsibility except where the pilot is being radar vectored and has not been assigned the responsibility for maintaining such clearance visually.
Obstacle/terrain avoidance while below the LSALT or MSA, as applicable, is a pilot responsibility except where the pilot is being radar vectored and has not been assigned the responsibility for maintaining such clearance visually.
