We don't need the tower/approach to tell the pilot...do not land, the field is closed.
Well, cannot disagree on that.
Just to give you an example of what I meant with 'too many rules and exceptions':
(CRAR United States)
In the U.S. 2 RVR values are required for CAT 2/3 approaches
TDZ and rollout value required. TDZ RVR controlling, rollout advisory only. Rollout may be substituted by mid (or if available far end) RVR.
So the first RVR value is
controlling, i.e. obligatory, the second one is
advisory only, i.e. it may have any value, you just need to have it 'heard' at one time. Whether you take that one into your considerations or not is up to you.
BUT...
With a certain CAT 3b minimum and a
fail operational landing system with
fail operational rollout control system the whole situation changes:
FAA Foreign Operations Specifications C060d (4):
Required RVR Reporting Equipment. The foreign air carrier shall not conduct any CAT3 operation unless the following RVR reporting systems are installed and operational for the runway of intended landing:
Fail-operational Landing Systems Using Fail-operational Rollout Control Systems.
- For CAT3 landing minimums as low as TDZ RVR 300 (75 meters), Mid RVR 300 (75 meters), and Rollout RVR (75 meters) require the following:- The TDZ, Mid and Rollout RVR reporting systems are normally required and are controlling for all operations.
- If one of these RVR reporting systems is temporarily inoperative, these operations may be initiated and continued using the two remaining RVR reporting systems. Both RVR reports are controlling.
So suddenly, and in contrary to the paragraph I mentioned above, you need 3 RVR values, and all are controlling. But hey, if one fails - no worries, just use the remaining ones.
Why not facilitate this whole thing and stick to the first paragraph? Why complicate things with the second one, saying you need three RVR values, all of them governing, and then just generate an exception to that just in the next sentence, basically saying 'Hey, you need three RVR values, but on the other hand, if one fails - two will do'?
While I completely understand your point of
these exceptions allow far more latitude on the part of the PIC
I think especially these paragraphs show the bureaucracy and is what I meant with my first post. Why not just keep it simple?
Regards,
DBate