A sideways look
Just to look at things a little differently;
A; In 1978 Lord Justice Denning made an observation in a case (Alidair V Taylor) likening aviation to the nuclear industry because of the potential fatal consequences of the slightest slip in the high standards expected and demanded. (perhaps someone can provide quote.)
B. ICAO Annex 10 is the basic and highest internationally recognised statement of requirements for the use of radio navigation aids in all-weather operations.
C. ICAO Annex 10 stated that irrespective of the operational objective, that the rate of a fatal accident during landing due to failures in the whole system, comprising the ground equipment, the aircraft and the pilot should not exceed in a million.
D. In Cat l this responsibility is vested more or less in the pilot…..
E. In Cat ll or lll the requirement must be inherent in the whole system.
F. ICAO Annex 10. Course bends are unacceptable when they preclude an aircraft under normal operating conditions from reaching the decision height in a stable attitude within 2degrees of pitch and bank and at a position from which a safe landing can be made.
G. ICAO Annex 10. For Cat ll and lll performance in the approach phase it is desirable to restrict course bends to displacements of less than fifteen feet either side of the centreline and vertical displacements of less than 4 feet at 50 feet – this allows approx. 30 feet of wheel height at the threshold…
H. ICAO Annex 10. Automatic and semi-automatic coupling is effected to a greater degree by the presence of bends.
I. Excessive control activity after the aircraft has settled on the an approach path may preclude it from successfully completing an approach or landing.
J. Doc 8071 stated; the purpose of flight testing should be to confirm the orrectness of the setting of essential signal-in-space parameters and determine the operational safety and acceptability of the ILS installation.
K. Doc 8071.Flight testing encompasses those tests carried out in the air by a trained crew in a specially equipped aircraft. These tests re required to examine the resulting signals in space as they are presented to an aircraft receiving system after being influenced by factors external to the installation;
L. Doc 9071 The flight test crew must be experts in their individual fields, have sound knowledge and experience in flight testing procedures and requirements. Their competency must be of a high order.
M. Doc 8071. Flight tests, because they represent in-flight evaluation and sampling of the radiated signal in the operating environment will continue to be an important final requirement in the proof of performance of a facility.
All italics are mine. All references were valid but may no longer be so. Perhaps someone could verify their validity for today.
ICAO documentation covers the complex significant topic of bends and gives some possible causes.
A bend may be permanent or transitory. A bend is a displacement of the received signal. An aircraft following a bend will appear to be on course. An aircraft unable to follow a bend sufficiently accurately or quickly enough will appear off course. To a pilot a bend can seem very similar to wake vortex, windshear or a sloppy autopilot/FMS.
Are these ICAO observations etc still valid and reasonable? A Lord Denning type view would be significant.
These ‘requirements’ should be referenced or enshrined in UK material. ICAO sought that wherever possible ICAO terminology should be carried into national material. Can terminology differences cause scope for confusion if the specific purposes of the use of each is not defined?
Is CAP 670 to radio navigation aids as airworthiness requirements are to the acceptability of aircraft and systems. Or similar Flight OPs requirements.
(For the non pilot community, Cat lll operations allow operations where no minimum cloud base is required and forward visibility against a very powerful light is not much further than the length of a large passenger aircraft. You ould not want to drive in it or even walk in it on a dark night. Try and visualise 15 feet, then four feet then 30 feet and reference it to your own height.)
There have been two recent fatal accidents where radio navigation aids have been involved and the ICAO system (the ground installation, the aircraft and pilot) has failed. Many years ago there was a very serious incident at Heathrow when a 747 on A Catlll approach supposedly came within 70 feet of the Penta Hotel. To my knowledge, that incident was never flight checked at all, let alone under similar conditions. (The subsequent jury in court were, I think, stated as having an average age of 26 and no knowledge of aviation other than as fare paying passengers.) The industry lost a significant opportunity and obligation to learn. Lets not wait for the accident to have a critical look at the system.
In the event of a failure of the ICAO system would you expect there to be a benign request for damages by the victims representatives? Look at some of the punative damages awarded. Look at the efforts made by the agencies elsewhere to trace the accountability of factors and responsible operators. Cork accident or the recent Schipol accident come to mind.
S.
It is possible that the previous posts have provoked consideration. It is not necessary for a response to indicate reaction. If someone in qualified authority is prepared to say that all is well, that would be good. Probably so too would be a statement that this is all rubbish and the product of the obsessed mind of SLF. - who owes me a Duty of Care and is it met?
Sin e.