- it isn't getting any clearer!

I'm not saying this is what happened, just that it's one possibility.

So it may be a complete coincidence that if you dialed up the FAC on your HSI, but were tuned to the VOR (maybe tuned enroute) the flight track would lead to the approximate crash site position. If one descended to the NP MDA for the G/S inop (which one might believe if unintentionally tuned to the VOR instead of the LOC) it seems from looking at the various charts and IAPs posted here that the flight track would pass very near the crash site. I say again, this is only ONE of several possible explanations for what happened.

As someone already pointed out, it's possible that the boys at the TSB lab know right now what frequencies were tuned in the radios and what was said in the cockpit. Time will tell.

Ref the possibility that they flew an "ILS" with the VOR dialled up, surely both pilots would have independently identified the ILS frequency before starting the approach?

Stranger things have happened. The NTSB report on the HOU Gulfstream accident linked somewhere above reveals that two highly experienced pro pilots did precisely that.

Of course that doesn't necessarily mean that the same thing happened here, but it's a possibility which might explain the facts as they are presently know to us. If newly revealed facts eliminate this possibility, then something else will have to explain the "new" facts.

The link to the above reference Accident Investigations - NTSB - National Transportation Safety Board

ILS/VOR Confusion
 

Regarding the discussion of the possibility of the AC flying the approach to the VOR instead of the ILS, it has been done before and therefore possible. The location and elevation of the wreckage is consistent.

I was an air traffic controller in YXS during the mid 70's when a CP Air 737 flight from YXJ nearly flew into Tabor Mnt. doing this very thing. Both pilots were fired.

For this to occur, both pilots have to fail to carry out the check list duties. Nevertheless, it happens.

The ancient FDR will only provide basic info so it will be of limited utility.

Regardless of what the max tailwind allowed may be, you must also consider the landing performance was on that day for the landing weight they had.

I don't know the usual landing distance for a 737, but 6,500 feet of gravel with a tailwind doesn't seem like a whole lot.

Was Jet A available in CYRB? Were they tankering fuel?

Were there any aircraft systems unserviceable that day?

Thrust reverse?
Anti-skid?
Spoilers?

All these factors could have contributed to a decision to circle for 17T.

It has been reported that 10 minutes elapsed from they time they reported "3 miles final for 35T" until they hit the hill. That implies either circling or multiple approaches to me.

Regarding flying an ILS on a VOR - I agree the track looks frighteningly matched, but as someone else has said, that does not require an FDR or CVR even to diagnose and will already be evident if it happened. I find it difficult to even contemplate as a possibility as it is 'un-charted'. We would have to be looking either a gross error by both crews - failure to brief, lack of cross-checks etc or a 'home-grown' procedure - maybe one of Rock's 'tend to push the envelope routinely', but surely with an ILS there................:confused: Does not make sense.

All those considering 'pushing the envelope' DO remember that g/a performance is affected too by 'excessive' tailwind.

BOAC:

1. The airport has no control tower (no ATC at all actually) so the pilot is free to circle in any manner so long as not restricted by the approach procedure.

2. Circling is in no way restricted from the ILS 35 T other than to remain within the TERPs circling maneuvering area for the correct approach category and not descend below MDA until in a position to make a normal descent to landing on Runway 17.

3. Circling with a left-hand pattern (over the higher terrain) gives the captain the best view of the airport at all times.

4. Circling with a right-hand pattern avoids the higher terrain (although remaining at MDA also avoids the higher terrain), but as a poster who knows the weather there says, the clouds are often lower over the higher terrain than they are to the west side. Right-hand circling requires an experienced F/O as he then is the one seeing the airport and when to turn base and final.

5. The winds that day, as one poster mentioned, somewhat favored a right-hand circle (on the west side of the runway).

These facts may or may not have anything to do with the accident.

I don't know if they were tankering fuel, but JET-A is normally available at CYRB, and without a call-out charge for the flight's ETA. FYI the distance from CYZF to CYRB is approx 842 NM.

Aterpster- I think I'll give up here. You just have your 35's and your left and right a bit confused! We are, I think all agreed that a left-hand circle (TO THE WEST!) off an ILS35 is the most sensible for a Captain flown pattern. I certainly give up on para 4!

These facts may indeed have a bearing on the accident.

Now I'm confused too BOAC!

Does circling to the left mean offsetting your circling maneuver to the left of (West) the FAC or does it mean that all turns will be to the left such as would happen if you offset to the right of (East) the FAC? I would have thought the latter myself as it's consistent with flying a left hand traffic pattern.

Best,

westhawk

westhawk:

you have it correct (not to be confused with right :))

Of course the initial turn off the Runway 35 localizer has to be a left westerly turn (say heading of 300 or 310 true) following by a right turn to parallel the runway, then a right turn to base, and finally a right turn to final.

That is a right-hand or right-hand-traffic if you will, circle to land.

This is from the U.S. AIM for airports with control towers:


Circle to land instructions:

Used by ATC to inform the pilot that he/she must circle to land because the runway in use is other than the runway aligned with the instrument approach procedure. When the direction of the circling maneuver in relation to the airport/runway is required, the controller will state the direction (eight cardinal compass points) and specify a left or right downwind or base leg as appropriate; e.g., “Cleared VOR Runway Three Six Approach circle to Runway Two Two,” or “Circle northwest of the airport for a right downwind to Runway Two Two.”

BOAC: Just make sure the rock is clutched in the correct hand. :)

Resolute passengers had no warning of crash - North - CBC News

Comments:

1. That beige rolling terrain has to be almost a worst-case scenario for trying to distinguish ground obstruction in scud (excepting darkness, of course).

2. The location of the VOR set off alarm bells in my mind right away. The crash site is certainly consistent with accidently flying a VOR radial 350 inbound instead of the ILS, but there are other possibilities, obviously...

3. ...such as a right turn (followed by a left turn) to enter a LEFT downwind and subsequent left hand turns to base and final (in my book, that is a "left" circle to land - but call it what you will). This gives the left-hand seat the best continuous view of the runway....

4. ....assuming the PIC, left seat, was actually handling the controls. In tricky conditions, probably a good assumption, but not a certainty. Much of the time, the pilot flying is the FO in the RIGHT seat.

I guess we'll know sooner or later, if the CVR and/or radio frequncy dials survived.

I'm with you BOAC. This was an ILS approach to 35. There is no reason that approach wouldn't have resulted in a landing. Wx is 300 sct at 3octas. 1000 OVC, at least it was 20 mins later. If their on the ILS, they make it. Why circle? Too much tailwind? 35 is an uphill runway, with about 100 feet difference between the button of 35 and the other end. There's no calls either and theres another aircraft somewhere out waiting to try, or actually trying, the 17 approach. Just don't see the Boeing crew launching off toward them with no calling the missed and advising that they were circling. If they were circling, they have a 1000 ovc above, they are going to circle over the much lower terrain to the left.

I say ILS to 35, but the scenario which seems to explain is the one about flying the approach with the VOR frequency selected instead of the ILS. That wouldn't result in a landing. Exactly what happened would happen. It would have been flown as a localizer approach as no glideslope indication, the wreckage is right on track, and the wreckage trail looks to start very close to minimums for that approach.

Only other possibility is a dodgy ILS. It was notamed us after the crash, which posters say is normal after this type of thing, and then test flown. Now its off till approx Aug 31. As you'd want to have that up and running as quick as possible, 10 days seems like a lot of downtime, unless they can't get a flight calibration machine in.

- right! The other one is dragging the wench along by her hair?

RH or LH circle to land
 

That's definitely not something you want personal opinions to thrive on... It's the same logic as with flying circuits:

- left hand = manoeuvring area is left of the runway as seen from final, you fly left turns (except for the break on the LOC)
- right hand is the corresponding opposite...

:)