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Unpublished let-downs

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Unpublished let-downs

Old 1st Feb 2017, 19:41
  #61 (permalink)  
 
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My understanding is a discrete procedure is supposed to be for a specific company to use and approved only for them (with an AOC?). Not sure if the Wellesbourne VOR procedure is strictly one of those - like you I used it in training.
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Old 1st Feb 2017, 20:48
  #62 (permalink)  
 
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Putting aside the wisdom or otherwise of using non-published procedures, the legalities for a private operation seem to allow it (in the UK).

I.e. the minima for IFR in the ANO and SERA do not apply when taking off or landing without any mention of following a defined procedure.

So it would seem reasonable that a procedure established and maintained to the same standards as a published one should offer a similar level of safety. The arguments about separation from other traffic are not much different from those for operating IFR outside controlled airspace except that you are in the vicinity of an airfield and hence more likely to encounter other traffic.

So, I agree using a hastily home-brewed approach carries increased risk, but a well thought out one done to the prescribed standards should be legal and relatively safe.
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Old 1st Feb 2017, 22:59
  #63 (permalink)  
 
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ANO:
Operating minima

(3) For flights under Instrument Flight Rules, the pilot in command must select and use aerodrome operating minima for each departure, destination and destination alternate aerodrome which—

(a)must not be lower than those notified, prescribed or otherwise designated by the relevant competent authority
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Old 2nd Feb 2017, 07:58
  #64 (permalink)  
 
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ANO:…
Nice try. But ignoring for a moment the issue that the ANO is not applicable to the operation of EASA aircraft, the 1000 ft rule for IFR in SERA is not part of aerodrome operating minima.

There are dead bodies and wreckage strew all over the place,
I'm still waiting for some one to come up with a persuasive list of examples of the "dead bodies and wreckage" attributable to unpublished let-downs. Most of those the examples I've seen cited are accidents that did not seem to depend on whether or not an approach was published or approved.
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Old 2nd Feb 2017, 08:21
  #65 (permalink)  

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I know of accidents where pilots messed up published IMC let-downs and others where pilots attempted to let down without any sort of pre-planned procedure. However, I can only think of one accident where an "unpublished" let down resulted in an accident and that occurred because the procedure wasn't followed at all accurately. Paradoxically, and sadly, a CAA Ops inspector was on board and perished along with the crew.

The same organisation suffered another, more recent and well publicised accident during an attempted IMC departure by a relatively inexperienced crew.
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Old 2nd Feb 2017, 09:04
  #66 (permalink)  
 
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Nice try. But ignoring for a moment the issue that the ANO is not applicable to the operation of EASA aircraf
Bookworm, I was replying to this:

I.e. the minima for IFR in the ANO and SERA do not apply when taking off or landing without any mention of following a defined procedure.
It's a thread, if you can follow it.
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Old 2nd Feb 2017, 12:37
  #67 (permalink)  
 
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Shy;

Is this the one you're refering to? http://www.aaiu.ie/node/11 The late great Spotty Muldoon was the examiner on board.

Another, more recent one: https://www.gov.uk/aaib-reports/aaib...y-s-76c-g-wiwi I think we both knew the crew from that, and we both definately knew this guy:https://www.gov.uk/aaib-reports/agus...3-october-2010

SND
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Old 2nd Feb 2017, 13:34
  #68 (permalink)  
 
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Hmm. All rotary.
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Old 2nd Feb 2017, 13:51
  #69 (permalink)  
 
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I know of accidents where pilots messed up published IMC let-downs and others where pilots attempted to let down without any sort of pre-planned procedure. However, I can only think of one accident where an "unpublished" let down resulted in an accident and that occurred because the procedure wasn't followed at all accurately. Paradoxically, and sadly, a CAA Ops inspector was on board and perished along with the crew.
Indeed if you are referring to G-HAUG, the primary cause was the deviation from the planned procedure. In the conclusions:

3.1.20 No evidence was found that would indicate that the aircraft would have experienced any difficulty in following the selected route, MOIRA - WARRN - MAP - B, if the aircraft had been operated throughout in the fully coupled mode, with Nav Capture, and allowed to fly the selected route without manual intervention.

There is an argument that a PANS-OPS compliant procedure would have offered more margin for error. But in general, deviating more than 1.3 miles from an RNP 0.3 final approach segment of a published procedure is also bad news.
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Old 2nd Feb 2017, 13:53
  #70 (permalink)  
 
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Would some one who is flying an unpublished approach in IMC below the safety altitude please inform the CAA with all the details if they feel it is legal and then let's see if they are prosecuted or not.
Hear hear. After all:

NCO.OP.110 Aerodrome operating minima — aeroplanes and helicopters

(a) For instrument flight rules (IFR) flights, the pilot-in-command shall select and use aerodrome operating minima for
each departure, destination and alternate aerodrome. Such minima shall:

(1) not be lower than those established by the State in which the aerodrome is located, except when specifically
approved by that State; and

(2) when undertaking low visibility operations, be approved by the competent authority in accordance with Annex V
(Part-SPA), Subpart E to Regulation (EU) No 965/2012.


So whether you operate iaw the ANO or Part-NCO, you may only descend below your minumum safe altitude in IMC if you are following an approved procedure.
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Old 2nd Feb 2017, 15:22
  #71 (permalink)  
 
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Your logic eludes me. Did you highlight the bit on "low visibility operations" for a reason? Where do you get "minimum safe altitude" from?
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Old 2nd Feb 2017, 16:49
  #72 (permalink)  
 
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Your logic eludes me
Clearly.

Where do you get "minimum safe altitude" from?
According to Skybrary, "Minimum Safe Altitude is a generic expression, used in various cases to denote an altitude below which it is unsafe to fly owing to presence of terrain or obstacles. An ICAO definition of the term "minimum safe altitude" as such does not exist." It is just a piece of jargon that a lot of seasoned pros would understand, like 'platform altitude' or any number of other phrases. Sorry it threw you.

Last edited by oggers; 2nd Feb 2017 at 17:03.
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Old 2nd Feb 2017, 22:15
  #73 (permalink)  

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Oggers,

I think you are reading more into that than is actually intended. It is about operating minima, as it says.

Your quote does not include any reference to descent below MSA or approved procedures.
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Old 3rd Feb 2017, 08:18
  #74 (permalink)  
 
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Shy, have a read of this:

Aerodrome operating minima (AOM) for IFR flights are set out in some detail. They are “selected and used” by the pilot-in-command. They cannot be lower than those established by the state in which the aerodrome is located, and cannot include low visibility operations (550 m RVR for approach, 400 m RVR for take-off) without a specific approval. Note that the 400 m RVR for take-off is higher than the 150 m required under the UK ANO.

AOM are in two parts:

Decision heights and minimum descent heights are specified in the implementing rules, and are calculated on the same basis as under most national rules and EU-OPS. The DH/MDH is usually the higher of the OCH or the system minimum for the approach aid.

Minimum RVRs and visibilities are set out in guidance material. In principle, the pilot is at liberty to select these within the constraints mentioned above. In practice, I suspect most will use those in the Guidance Material or published by Jeppesen, which are substantially the same as for CAT.
The author participated in the Part-NCO review group in 2010, working with EASA and other stakeholders on the text of Part-NCO.
It is pretty clear to me that whatever discretion private operators had to exploit homebrew approaches back in the day no longer exists.
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Old 3rd Feb 2017, 08:52
  #75 (permalink)  
 
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ROTFLMAO.
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Old 3rd Feb 2017, 10:54
  #76 (permalink)  

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Oggers, it refers to the bit at the end of an approach, no reference to MSA.
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Old 3rd Feb 2017, 14:56
  #77 (permalink)  
 
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ShyTorque

Oggers, it refers to the bit at the end of an approach, no reference to MSA.
Yes the approach. That is what gets you down from safety altitude to minimums. I have shown you the regs. You are interpreting them differently from me, so here is some further guidance from the CAA:
User-defined approaches can be dangerous and are not authorised. [Safety Sense Leaflet #25]

For operations in IMC, below safety altitude the use of user waypoints, and modification of the published procedure using temporary waypoints or fixes not provided in the database, is potentially hazardous and should never be attempted. The manual entry of coordinates into the RNAV system by the flight crew is not permitted for RNAV operations within the terminal area and should never be done below safe altitude in any location. [CAP 773 Flying RNAV (GNSS) Non-Precision Approaches in Private and General Aviation Aircraft]
It is in the ANO, it is in Part-NCO, it is spelled out in CAP773. You cannot descend below safety altitude in IMC unless you are using an approved procedure.
.
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Old 3rd Feb 2017, 15:00
  #78 (permalink)  
 
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Originally Posted by oggers View Post
ShyTorque



Yes the approach. That is what gets you down from safety altitude to minimums. I have shown you the regs. You are interpreting them differently from me, so here is some further guidance from the CAA:
User-defined approaches can be dangerous and are not authorised. [Safety Sense Leaflet #25]

For operations in IMC, below safety altitude the use of user waypoints, and modification of the published procedure using temporary waypoints or fixes not provided in the database, is potentially hazardous and should never be attempted. The manual entry of coordinates into the RNAV system by the flight crew is not permitted for RNAV operations within the terminal area and should never be done below safe altitude in any location. [CAP 773 Flying RNAV (GNSS) Non-Precision Approaches in Private and General Aviation Aircraft]
It is in the ANO, it is in Part-NCO, it is spelled out in CAP773. You cannot descend below safety altitude in IMC unless you are using an approved procedure.
.
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Old 3rd Feb 2017, 15:05
  #79 (permalink)  
 
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^^^^^^^^^^^^^^^^
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Old 3rd Feb 2017, 15:49
  #80 (permalink)  
 
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All right. I've recovered my composure enough to type again…

Aerodrome operating minima are established for aerodromes for take-off and landing. They consist of a decision height or minimum descent height and an associated visibility condition for each approach. Aerodrome operating minima may be published by the state, although these days the UK simply adopts what it says in the corresponding part of the EASA Air Ops Regulation, in this case Part-NCO.

The rule that you want to apply as "MSA" is in Part-SERA.

SERA.5015 Instrument flight rules (IFR) — Rules applicable to all IFR flights
(b) Minimum levels
Except 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.


The 1000 ft mentioned in (b) is not part of "aerodrome operating minima". It is a generic rule for IFR flight that applies except when necessary for take-off or landing.

Descent below the levels addressed in SERA.5015(b)(2) when taking off or landing is not to be taken lightly. The best way of mitigating risk is to use a PANS-OPS compliant instrument approach procedure if available. Almost all CAT operations manuals will require that if relatively conservative minima for a visual approach are not met. But there is no requirement that a published procedure is used to meet the requirements of SERA.5015(b) when operating under Part-NCO.
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