<font face="Verdana, Arial, Helvetica" size="2">I have been doing a bit of checking through the ANO in my spare time (sad, I know).</font>
No sadder than my contributions, and, as you pointed out, I did start it!
<font face="Verdana, Arial, Helvetica" size="2">What might catch you legally is Article 14 (7) which says that any equipment used for navigation, including 'information from selected celestial bodies'(or something like that) must be approved by the CAA. As I understand it a GPS fitted into an aircraft becomes a mod which must be approved. A handheld one doesn't, provided you don't attach it to the yoke.</font>
That's a very fine attempt but I don't think GPS qualifies -- it's a trilateration (distance measuring) technique and the article seems to be refering to altitudes and bearings from stars.
<font face="Verdana, Arial, Helvetica" size="2">In addition, Article 15 says equipment carried must be in a serviceable condition and of a type approved in relation to the purpose it is used. If GPS is not approved as an ADF substitute then you are stuck.</font>
That's certainly getting closer. But it refers to installed equipment, and therefore not handheld GPSs. It's certainly arguable that a panel-mount GPS with a Flight Manual supplement saying "VFR-only" could not be used to fly an IFR approach.
<font face="Verdana, Arial, Helvetica" size="2">Article 16 says that all radio equipment must be approved. Does GPS come under radio equipment?</font>
I'm not quite with that. Article 16 appears to say that all
required equipment must be serviceable.
<font face="Verdana, Arial, Helvetica" size="2">What I couldn't find were any details on the approval or otherwise of GPS.</font>
I don't know of any in the ANO. GPS seems to have a funny status -- certain units can be used to satisfy BRNAV requirements.
<font face="Verdana, Arial, Helvetica" size="2">However, it is clear that you must not descend below MSA except for purpose of landing and on an approach procedure unless you are below 3000' AMSL and clear of cloud and in contact with the ground. As far as I know there are no approved GPS approaches in this country.</font>
This is the contention that I really have trouble with. The Rules of the Air don't say anything of the sort!
Rule 29 says:
"Without prejudice to the provisions of rule 5, in order to comply with the Instrument Flight Rules an aircraft shall not fly at a height of less than 1000 feet above the highest obstacle within a distance of 5 nautical miles of the aircraft unless:
(a) it is necessary for the aircraft to do so in order to take off or land;
(b) the aircraft is flying on a route notified for the purposes of this rule;
(c) the aircraft has been otherwise authorised by the competent authority; or
(d) the aircraft is flying at an altitude not exceeding 3000 feet above mean sea level and remains clear of cloud and in sight of the surface."
It says nothing about "on an approach procedure" or anything of the sort. Just if "it is necessary for the aircraft to do so in order to take off or land".
What seems to be "obvious" but missing is any requirement to:
a) make use of an IAP
b) use particular equipment when flying an IAP
Let's just get this thing in perspective. I'm not seriously suggesting that it's wise to make up approach procedures, or rely on a handheld GPS in circumstances when it's operation is critical. (I think it's equally if not more daft to rely on an ADF!) What I am saying is that outside controlled airspace UK air law places few restrictions on the pilot to operate in a particular way. That requires a healthy and thorough attitude to risk management.
I think that the attitudes pushed by the CAA of continually damning GPS distort the ability to manage risk and present an unhelpful picture which is at odds with most pilots' everyday experiences. When you keep getting "advice" which is blatantly at odds with experience and common sense, you learn to ignore it. There
are real risks with GPS.
I do not believe that the CAA does pilots any favours by accepting 'status quo' technologies, while placing great burdens on the introduction of new and clearly superior technologies. The FAA has had a GPS overlay program for more than 5 years, and I've not even read of an incident let alone an accident attributed to a GPS approach.
It's all very well for AP to sit there and say to airport operators "sure, we'll consider your request for a GPS approach -- just make out the cheque to...". The FAA had the foresight to realise that GPS could be an enormous benefit to civil aircraft safety, and to move forward in a way that improved overall IFR safety. But it wasn't invented here, was it?