Erebus AGAIN?!

January 14th, 2012

Article by Danielle Bruckert
Co-Author, Cessna Training Manual Series

- Was There Perhaps Something Else We Overlooked?’

On a recent visit to New Zealand, I was intrigued to find yet another book propounding the popular theory that the pilots did no wrong, and more widespread sympathy by the NZ public for the poor deceased crew, and the terrible injustice done by the tyranical airline in trying to blame them. This post is probably going to stir alot of snow over the resting place of the pilots, and I apologise to the victims families for doing that, but I feel it needs to be said.

I teach a course on Multi-crew Co-operation, that is teaching pilots how to maximise the effect of having two people in the cockpit, to ensure that the whole is strengthened by the sum of the parts. While researching material for our presentations, I came across the CVR transcripts for the Erebus accident.

I’ve always had a suspicion about what happened, and reading the conversations from the cockpit voice recorder, confirmed it. However I provide this article to let you decide for yourself, without bias.

A Brief Summary of Accident:

At 19.17h (27 November) Flight TE901 took off for a scenic flight from Auckland over Antarctica(McMurdo). Approaching Ross Island it appeared that the area which was approved by the operator for VMC descents below 16000ft was obscured by cloud. The crew decided to descend in a clear area to the (true) North of Ross Island in two descending orbits. The aircraft’s descent was continued to 1500ft on the flight planned track back toward Ross Island for its next turning point, Williams Field, McMurdo. The aircraft however, was actually flying 1,5Nm East of its flight-planned track. Shortly after reaching 1500ft the GPWS sounded. Go around power was applied but the aircraft struck the slope of Mt Erebus at 1465ft. The aircraft broke up and caught fire.

To sum up a debate that fills several books:

The PROBABLE CAUSE as submitted by the initial Commission of Inquiry read: “The decision of the captain to continue the flight at low level toward an area of poor surface and horizon definition when the crew was not certain of their position and the subsequent inability to detect the rising terrain which intercepted the aircraft’s flight path.” An investigation by the Royal Commission of Inquiry overruled this, stating “The dominant cause of the disaster was the act of the airline in changing the computer track of the aircraft without telling the air crew.”, adding contributing factors as the lack of any chart showing a printed route, and the effects of sector whiteout. the final waypoint had been changed from longitude 166deg 48.0′ E (the Williams Field NDB) to 164deg 48.9′ E by mistake, three years previously, routing 7 flights down the middle of McMurdo Sound.

What’s new?

Consider, first, the primary rule in Instrument Flight Rules (IFR) for a visual descent: The pilot of an aircraft inder IFR may request to descend in VMC, only if it is assured they can maintain VMC, and subject to maintaining their own terrain clearance.

Highlighting the phrases below from the CVR, ask your self, was this crew certain they could maintain VMC when they began the descent, and when they continued the descent?

CA = Captain, FO = First Officer, FE = Flight Engineer, gu = Guide, MC = McMurdo Centre

4:04 CA I think we’ll start down early here.
FO OK, I’ll see if I can get hold of VHF
12,18 MC We have a low overcast in the area at about 2000ft and right now we’re having some snow, but visibility is still about 40 miles and if you like I can give you an update on where the cloud areas are around the local area.
FO Yes 901, that would be handy. We’d like to descend and maintain flight level one six zero.
MC Kiwi 901, Mac Centre descend and maintain flight level one six zero.
MC 901, this is the forecaster again. It looks like the clear areas around McMurdo area are at approximately between 75 and 100 miles to the northwest of us but right now over McMurdo we have a pretty extensive low overcast. Over.
12,19 FO Roger, New Zealand 901, thanks.
FE That’ll be round about Cape Bird, wouldn’t it?
FO Right, right.
FE Got a low overcast over McMurdo.
CA Doesn’t sound very promising, does it?
MC Within range of 40 miles of McMurdo we have radar that will, if you desire, let you down to 1500ft on radar vectors. Over.
FO Roger, New Zealand 901, that’s acceptable.
12:20 CA That’s what we want to hear.

12,31 CA I’ll have to do an orbit here, I think.
CA Well actually it’s clear out here if we get down.
FE It’s not clear on the right-hand side here.
FO No.

CA If you can get HF contact tell him that we’d like further descent. We have contact with the ground and we could, if necessary, descend doing an orbit.
12,32 FO We’d like further descent and we could orbit in our present position which is approximately 43 miles north, descending in VMC.
MC Roger Kiwi New Zealand 901, VMC descent is approved and keep Mac Centre advised of your altitude.

FO Roger, New Zealand 901, we’re vacating one eight zero. We’ll advise level.
12,34 CA Captain again, ladies and gentlemen. We’re carrying out an orbit and circling our present position and we’ll be descending to an altitude below cloud so that we can proceed to McMurdo Sound.
FE There’s Wilson.
12,35 FO Transponder is now responding.
FE Still no good on that frequency though?
FO No.

FO Roger 901, you are now loud and clear also. We are presently descending through flight level one three zero, VMC, and the intention at the moment is to descend to one zero thousand.

12,36 FO We’ve lost him again.
FO I’ll go back to HF, Jim.
CA I’ve got to stay VMC here so I’ll be doing another orbit.
12,38 FO 901, we briefly had contact on one three four one. We’ve now lost contact. We’re maintaining 10000ft, presently 34 miles to the north of McMurdo.

CA Tell him we can make a visual descent on a grid of one eight zero and make a visual approach to McMurdo.

12,42 FO 901, still negative contact on VHF. We are VMC and we’d like to let down on a grid of one eight zero and proceed visually to McMurdo.
MC New Zealand 901, maintain VMC. Keep u advised of your altitude as you approach McMurdo..

CA We’re VMC around this way so I’m going to do another turn in.
CA Sorry, haven’t got time to talk, but …
gu Ah well, you can’t talk if you can’t see anything.
12,43 gu There you go. There’s some land ahead.
CA I’ll arm the nav again.
12,44 FO Roger, New Zealand 901, 50 miles north the base was one zero thousand. We are now at 6000 descending to 2000 and we’re VMC.
12,45 CA We had a message from the Wright Valley and they are clear over there.
gu Oh, good.
CA So if you can get us out over that way…?
gu No trouble.
gu Taylor on the right now.
gu This is Peter Mulgrew speaking again folks. I still can’t see very much at the moment. Keep you informed soon as I see something that gives me a clue as to where we are. We’re going down in altitude now and it won’t be long before we get quite a good
12,46 FE Where’s Erebus in relation to us a the moment.
gu Left, about 20 or 25 miles.
FO Yep,yep.
FE I’m just thinking of any high ground in the area, that’s all.
gu I think it’ll be left.
FE Yes, I reckon about here.
gu Yes … no, no, I don’t really know.
12,47 gu That’s the edge.
CA Yes, OK. Probably see further anyway.
FO It’s not too bad.
gu I reckon Bird’s through here and Ross Island there. Erebus should be there.
CA Actually, these conditions don’t look very good at all, do they?
gu No they don’t.

12,49 gu That look like the edge of Ross Island there.
FE I don’t like this.
CA Have you got anything from him?
CA We’re 26 miles north. We’ll have to climb out of this.

gu You can see Ross Island? Fine.
FO You’re clear to turn right. There’s no high ground of you do a one eighty.
CA No … negative.
GPWS Whoop, whoop. Pull up. Whoop whoop.
FE Five hundred feet.
GPWS Pull up.
FE Four hundred feet.
GPWS Whoop, whoop. Pull up. Whoop whoop. Pull up.
CA Go-around power please.
GPWS Whoop, whoop. Pull -.

Once the crew started manoeuvring to maintain VMC (visual meterological conditions), they took navigation by visual reference into their own hands.

Again, ICAO states a VMC descent may be initiated provided the crew are ASSURED of maintaining VMC.

So, were they?

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