IR approaches into private sites? (UK)
Seems to me the Irish S76 accident was really not the fault of a GPS approach - it was more about pilots simply not performing the approach they intended, accurately
What accuracy should they have maintained? What were the dimensions of the primary and secondary protected areas for this initial approach segment? What Flight Technical errors, pilot reaction times and wind speeds were used when determining the turn radius and ground track? What descent gradient was assumed etc etc
The simple fact that they hit the ground 1.36nm offset from the intended track - in this phase of the approach - shows that this procedure did not meet any normal design standard. If that does not constitute
accidents into private sites as a direct consequence of an unapproved IFR let downs
To put a perspective on it, there is a VOR procedure at a neighbouring airport here that has a 14nm outbound leg with a descent from 3500' to 2000', prior to a procedure turn. If you hit terrain 1.36nm at the end of that leg you would have tracked in error by 5.5° . Given that the normal tolerance for IR testing - not the procedure design - is 5°, do you think CFIT would be a reasonable outcome for a 0.5° error?
As an aside, it's easy to concentrate on the approach phase in isolation - what about the missed approach? Imagine climbing out from this missed approach point on one engine
Last edited by 212man; 24th Aug 2010 at 05:41.
And more importantly, who calculated the DH/MDH and based on what pressure setting?
The most dangerous thing about such approaches in my mind is the same mindset that prompts a pilot to carry one out in the first place will be the same mindset that keeps him going that bit further down the approach to get visual rather than throw it away.
The most dangerous thing about such approaches in my mind is the same mindset that prompts a pilot to carry one out in the first place will be the same mindset that keeps him going that bit further down the approach to get visual rather than throw it away.
And more importantly, who calculated the DH/MDH and based on what pressure setting?
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212man
Given the local terrain in the S76 accident I fully agree that the GPS approach here did not meet any normal design standard, which meant high standards of accuracy were necessary. The pilots should have maintained an accuracy to keep themselves well away from the hills. With GPS a lateral tolerance of 250m could have been achieved. Had the approach been overlayed as a route on a moving map their error would have been obvious and probably avoided. This was not an example where the pilots were trying hard and did a good job endeavouring to fly the approach well - it was very casually undertaken, which was the problem. A published approach flown with similar attitude could have had similar consequences.
Your example of the 5 deg tolerance highlights the inaccuracy of a VOR approach compared with GPS. With a VOR or NDB approach a tolerance measured in degrees is all that can be used, and this results in a large tolerance at distance. A GPS approach will obviously have a spatial tolerance regardless of distance from the landing site and be far more accurate over most of the approach.
To be clear, I am not actually defending this S76 approach - just saying the reason this accident occurred was fundamentally poor piloting and CRM.
Given the local terrain in the S76 accident I fully agree that the GPS approach here did not meet any normal design standard, which meant high standards of accuracy were necessary. The pilots should have maintained an accuracy to keep themselves well away from the hills. With GPS a lateral tolerance of 250m could have been achieved. Had the approach been overlayed as a route on a moving map their error would have been obvious and probably avoided. This was not an example where the pilots were trying hard and did a good job endeavouring to fly the approach well - it was very casually undertaken, which was the problem. A published approach flown with similar attitude could have had similar consequences.
Your example of the 5 deg tolerance highlights the inaccuracy of a VOR approach compared with GPS. With a VOR or NDB approach a tolerance measured in degrees is all that can be used, and this results in a large tolerance at distance. A GPS approach will obviously have a spatial tolerance regardless of distance from the landing site and be far more accurate over most of the approach.
To be clear, I am not actually defending this S76 approach - just saying the reason this accident occurred was fundamentally poor piloting and CRM.
rotorspeed , ok then, we just need to super-pilots never doing little errors...
The problem was flying that app in the first place, not a bad pilot performance.
There is a NEED for a margin, always. No matter how precise the aids are.
I've been in similar apps and I will not be there again. For me IMC over terrain = published IFR flight and app (or offshore ifr), if not, I don't want the job.
You will not get to the retirement doing that for ever...
Best regards
Aser
The problem was flying that app in the first place, not a bad pilot performance.
There is a NEED for a margin, always. No matter how precise the aids are.
I've been in similar apps and I will not be there again. For me IMC over terrain = published IFR flight and app (or offshore ifr), if not, I don't want the job.
You will not get to the retirement doing that for ever...
Best regards
Aser
EASA ROA vs. private helicopter approach/takeoff in IMC under VFR
I'm augmenting this thread of to me (Austrian) very peculiar
"UK approaches" in IMC under VFR (IFR would need ATC guidance, publiced procedures, not?)
The Ballyedmond incident was an ac operating under private pilots rules, albeit conducted by CPLs, clearly in IMC, flying their own GPS guided approach to a private helipad.
A) Is any of that legal under EASA regulations?
If yes, what are the limitations, license- wearther-limits- or type-of-operation- wise.
B) Is it still legal under CAA ruling (G- reg, grandfathered, etc) ?
"UK approaches" in IMC under VFR (IFR would need ATC guidance, publiced procedures, not?)
The Ballyedmond incident was an ac operating under private pilots rules, albeit conducted by CPLs, clearly in IMC, flying their own GPS guided approach to a private helipad.
A) Is any of that legal under EASA regulations?
If yes, what are the limitations, license- wearther-limits- or type-of-operation- wise.
B) Is it still legal under CAA ruling (G- reg, grandfathered, etc) ?
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Thx, interesting read.
So, whats the EASA's current (2015) stance on IFR flights outsde controlled airspace, especially in IMC?
So, whats the EASA's current (2015) stance on IFR flights outsde controlled airspace, especially in IMC?
Last edited by Reely340; 13th Oct 2015 at 10:22.
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SERA.5015 Instrument Flight Rules (IFR) - Rules Applicable to All IFR Flights
(a) Aircraft Equipment
(a) Aircraft Equipment
Aircraft shall be equipped with suitable instruments and with navigation equipment appropriate to the route to be flown and in accordance with the applicable air operations legislation.
(b) Minimum LevelsExcept when necessary for take-off or landing, or except when specifically authorised by the competent authority, an IFR flight shall be flown at a level which is not below the minimum flight altitude established by the State whose territory is overflown, or, where no such minimum flight altitude has been established:
(1) over high terrain or in mountainous areas, at a level which is at least 600 m (2 000 ft) above the highest obstacle located within 8 km of the estimated position of the aircraft;
(2) elsewhere than as specified in (1), at a level which is at least 300 m (1 000 ft) above the highest obstacle located within 8 km of the estimated position of the aircraft.
(2) elsewhere than as specified in (1), at a level which is at least 300 m (1 000 ft) above the highest obstacle located within 8 km of the estimated position of the aircraft.
Last edited by puntosaurus; 15th Oct 2015 at 12:48. Reason: Correct a mistake in the CAA consolidated version
Except when necessary for take-off or landing,
Avoid imitations
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hence self-positioning GPS letdowns, IMC with no idea what traffic or obstacles are in the way.
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The UK CAA will not allow you to write a PART-OPS operations manual that gives you as much operational freedom as the legislation. They insist you write something like:
Non-commercial ops, are currently outside this, but with PART-NCO/NCC on the way in, that may be tightening up too.
Except when necessary for take-off or landing in accordance with a published procedure promulgated in the relevant national AIP.
