Can anyone advise the date that Captain Wilson was supposed to have advised the crew that any altitude the McMurdo Radar allowed them to descend to was actually made?
Captain Wilson confirmed that during his briefings given in 1978 and 1979 crews were told that they could descend to any height authorised by the USN Air Traffic Controller.
The statement by Megan that the radar could not monitor the approved descent procedure has also proven to be incorrect or is he is accusing Vette of an "absurdity".
Vette said,
Their optimism rose as the radio from McMurdo came on with its offer: ‘Within a range of 40 miles of McMurdo we have radar that will, if you desire, let you down to 1500 feet on radar vectors.
‘Roger, New Zealand nine zero one. That is acceptable,’ replied Cassin.
Collins expressed his relief. ‘Crikey, that’s what we Want to hear.’
He eased back slightly on the three power levers, thinking maybe the briefing was wrong and they could pick up the aircraft above 6000 feet, and beyond 40 miles.
They were now passing over a thinning belt of stratus through which the fragmented pack ice showed. But only a short way ahead, a big break of some 40 by 20 miles, broken only by a few fluffy clouds, was showing up.
The safe course was to descend into this space in an orbit which would bring them around and back onto the navigation track again.
From where they were the base of the major cloud areas appeared to be about 10,000 feet. Once they got below this, they could be in the clear with miles of visibility to continue the run up McMurdo Sound until intercepted by radar.
If conditions proved unsatisfactory once they descended into the clear opening, then there would be no problem climbing back to 18,000 feet, and flying on to McMurdo waypoint, before doubling back to do a run over the Dry Valley on the Victoria Coast mainland — which they could still see was in sunshine.
The aircraft, locked on to 18,000 feet, was still {lying in crystal sunshine. Elusive glimpses of pack ice showed through the scattered cloud below, and the tantalising knowledge that the land was close at hand kept the crew on visual tenterhooks, scanning keenly for the white glow of sun on snow, and the darker patterns of rock. It was some consolation for the crew that the radar was operating, and that the Americans were happy for them to fly over the ice airfield at 1500 feet.
There was a nagging doubt at the back of Jim Collins’ mind, possibly associated with the briefing, that the approach radar would be unable to pick them up above 6000 feet. On previous flights the approach had been largely clear of cloud and, as a sure aid, the feed in had been attained by using McMurdo’s NDB (Non-Directional Beacon) to bring them into the orbit of the precision approach radar, at 6000 feet.
The controller was expecting them to come down the sound, as all the other aircraft had, and in accordance with the flight plan they had held for the last 14 months.
The agreement between the airline and CAA in August 1977 for an authorised letdown to 6,000 feet in the designated area south of Ross Island was regarded by the Americans, when they found out about it, after the disaster, as quite impractical. In the view of Chief Warrant Officer Priest, who was chief traffic controller and Mac Centre Supervisor during the 1979/80 season, this 6,000 feet sector was “absurd” because of the inability of radar control in that sector.
So they guy in charge of McMurdo said it was an absurdity, but your saying he was wrong?
" There was a briefing a few days prior to the flight where the crew were told that the route was well to the side of Mount Erebus." Not true. The crew were told that the final waypoint was at McMurdo Station. There can be no dispute about this, because it was recorded on tape.
Chippendale,
An examination of this briefing revealed certain significant items were not included, The way in which the Air New Zealand route varied from the normal military route, which followed the reporting points depicted on the RNC, particularly on the leg from Cape Hallett south to McMurdo.
So
ampan, what is your interpretation of what Chippendale said? He's not correct? The audio did say "to McMurdo", but all the maps, photos and sample flight plan indicated down the sound. In any event, the mention of McMurdo would mean very little for the simple fact the waypoint down in the bottom of the sound, where Collins thought he was going, was also called McMurdo on the flight plans. Right royal cock up heh?