As an aside
as quoted previously the rules say:-
(1) Subject to paragraph (6), an aircraft flying outside controlled airspace at or above flight level 100 shall remain at least 1,500 metres horizontally and 1,000 feet vertically away from cloud and in a flight visibility of at least 8 km.
(2) Subject to paragraphs (3), (4), (5) and (6), an aircraft flying outside controlled airspace below flight level 100 shall remain at least 1,500 metres horizontally and 1,000 feet vertically away from cloud and in a flight visibility of at least 5 km.
(3) Paragraph (2) shall not apply to an aircraft which:
(a) flies at or below 3,000 feet above mean sea level;
(b) remains clear of cloud with the surface in sight; and
(c) is in a flight visibility of at least 5 km.
(4) Paragraph (2) shall not apply to an aircraft which is not a helicopter and which:
(a) flies at or below 3,000 feet above mean sea level;
(b) flies at a speed which, according to its air speed indicator, is 140 knots or less;
(c) remains clear of cloud with the surface in sight; and
(d) is in a flight visibility of at least 1,500 metres.
So if you were above a low layer of cloud you could at least technically be clear of cloud, in flight vis of at least 1500 m horizontally, with varying amounts of the surface in sight, from a lot, to very small holes.
It clearly becomes a decreasingly good idea to do such a thing, in proportion to the percentage of cloud, but is there/was there ever an official definition of the ratio of hole to cloud necessary for the surface to be defined as being in sight?
And yes, Amy Johnson and others have died of going over the top of cloud layers
Last edited by astir 8; 22nd May 2012 at 07:29.