What's modified when a gravel kit is specified?

Ross...

From the Boeing tech website:

"Whatever surface was to be used, certain guidelines had to be observed. The surface had to be smooth with no bumps higher than 3 inches in 100ft; good drainage with no standing water or ruts; and the surface material had to be at least 6 inches thick with no areas of deep loose gravel. Boeing offered a survey service to assess the suitability of potential strips. If a surface was not particularly hard it could still be used by reducing tyre pressure down to a minimum 40psi in accordance with a chart.

The Boeing "unpaved Strip Kit" components include:
Nose-gear gravel deflector to keep gravel off the underbelly.
Smaller deflectors on the oversized main gear to prevent damage to the flaps.
Protective metal shields over hydraulic tubing and brake cables on the main gear strut.
Protective metal shields over speed brake cables.
Glass fibre reinforced underside of the inboard flaps.
Metal edge band on elephant ear faring.
Abrasion resistant Teflon based paint on wing and fuselage undersurfaces. Strengthened under-fuselage aerials.
Retractable anti-collision light.
Vortex dissipators fitted to the engine nacelles.
Screens in the wheel well to protect components against damage."

More info can be found at: http://www.b737.org.uk/unpavedstripkit.htmI

I was aboard a PWA B737 conducting tests of the effectiveness of the kit components at various unimproved strips in the Pacific Northwest waaaay back in 1971.

Thanks Grizz, as I was puzzled by different bits of the kit when I saw its photos. Btw, this link works better:
Unpaved Strip Kit

The operation, as any viable business, whether subsidized by the state or not, has to be cost based. Or would you be in the business of giving away candy? "High fuel and maintenance costs" are universal. The rest, including pricing your product, is a management factor. :ooh:

Punkalouver wrote:As I recall with older GPWSs with gear down and flaps in any landing position, no further warnings. And the old radio altimeters sure don't talk to you. So both ZBBYLW and Lost in Saigon have it right.

Either you don't know what you are talking about punkalouver or you have forgotten... It's even described on Wiki. :=

Lost in Siagon:

It didn't nor did I state or imply that it did.

I was thinking in terms of economics of operations.

As a geologist (but not a pilot), I've flown in and out of Resolute many times over the course of 40 years or so, so am familiar with the area.
I'm pretty sure that the wreckage trail shown in purple on Aterpster's map is incorrect. Judging by the photo posted by Downnorth (post #8), the trail ends to the right (south) of the stream cut, which is very apparent in the topographic map. I would imagine the wreckage trail is actually roughly parallel to the runway
I would be very surprised if it turns out that the pilots had decided to attempt a landing on Rwy17. In my experience, back course approaches at Resolute are almost never done.

So, your estimate is that the initial impact was Southeast of the 587' elevation on aterpster's map?



http://i201.photobucket.com/albums/a...er/CYRBCTL.jpg

Has it been established which way the wreckage trail runs? Does 'X' mark initial or final point? There could almost be a fuel spill line running to the right of the main fuselage part. I'm not sure the exact location of where the poor souls died is too critical - altitude and direction of flight will be more so?

direction of flight
 

I'm thinking they were still northbound, based on the wreckage trail. Light stuff stays put heavier stuff moves in the direction of the flight and it sort of looks like engine components are to the left in the picture. Perhaps they were visual and circling, Captain flying from the left seat so he widens to the right to keep the runway in sight. In low vis he may not have had good visual detail of the terrain and flew right into in. The relatively long wreckage trail, and the fact there were survivors suggest controlled flight into terrain at relatively shallow impact angle.

Maybe, but at what altitude....?

Earlier message deleted.

As for circling, I suspect a red herring. Why would you circle when there is more than one straight-in approach to similar minimums for runway 17. Why not just do the ILS and land with a tailwind within limits.

Rockhound:
　
The wreckage trail is an approximation. But, the point of impact is from AvHerald and is in conformance with the photo you refer to. The point is, it appears he crashed within the Runway 35 ILS T circle to land area. My circle to land areas are indisputable.

That means you don't understand the circle to land option on many instrument approach procedures, including this one. I don't mean to be negative, but the nuances of an instrument approach procedure are not learned overnight by pilots.

As to the back course approach another pilot flew that just before the crash and missed the approach because of a low cloud deck. He tired the back course approach again with better weather a bit later, and saw the burning wrecking as he broke out of the clouds on final approach to Runway 17.

In the photo in post #8, the wreckage pile on the right includes the tail so the motion of the aircraft must have been from right (south) to left (north). The trail does not cross the stream cut. The "x" in Aterpster's map may well mark the impact point accurately.
I still find the suggestion that he was circling to land on Rwy 17 difficult to accept. A tailwind of 10-15 knots straight down the runway should present no difficulties for a 737.

Well, if in motion..., you never know, unless on video.

CYRB Approaches....
 

I've shot approaches to both sides (17/35T), numerous times, both in PWA/Canadi>n Airlines B7372s and Hercs. What to say other than its a very sad day up there. We can sit here all we want and try and 'figure out' what was going on there but in the end,some of the answers will be found on the FDR, and CVRs if the data is good, and by the investigators who are charged at trying to figure out what really went wrong.

There are so many variables about flying into Res'...if there was fog, then it can be a real can of worms. The fog takes on a life of its own up there, depending on the prevailing wind. Sometimes, what one expects to see and what actually 'is' are two different things. Let me say that flying in the Canadian high arctic was some of THE most demanding flying that a pilot could ever experience, on a good day...when was the last time that any of you ever used 'destination grid' and 'grid offsets' or ever aligned your compasses with a sextant, prior to the approach? Why you ask? Magnetic compasses don't work up there and the gyros have to be manually aligned because they aren't slaved.
'Thoughts are with the families who lost a loved one in this'. Its never easy.

Rockhound:

Check this site. It has a second photo that better shows the wreckage distribution. The text also indicates the flight reported on final for Runway 35:

Crash: First Air B732 near Resolute Bay on Aug 20th 2011, impacted terrain

I might be way off base but something about the wreckage does not look right.

I really don't think anyone reading this thread is interested in "economics of operations". They are either grieving the loss or trying to figure out how it could have happened.

In any case your suggestions of "economics of operations" are incorrect.

This was a privately chartered cargo aircraft that also is configured to carry passengers. I am quite sure it would have been filed to capacity with cargo and would have been operated as economically as possible. Cargo charters are the only lifeline to remote communities such as this. Everyone in the far north knows fully well what it costs to maintain a community in such a remote location.

But, even if the person who chartered the aircraft chose to fly it half empty, why would that be worth commenting on?

CYRB First Air 737 crash
 

After reading the Aviation Herald article and comments;

Crash: First Air B732 near Resolute Bay on Aug 20th 2011, impacted terrain

I am concerned that, given the perceived impact location and track of the debris field, the a/c may have been chasing a false localizer course. The location’s offset from the localizer’s centreline (localizer being a couple of thousand feet past the stop-end in this case) suggests a possible false course. This ILS is thirty years old plus (and a second hand installation . . . used elsewhere before Resolute). ICAO deemed this ILS model unacceptable . . . no longer to be installed as of about the end of the 1990’s. This model has had a know history of false courses.

The installation is somewhat “unique” and apparently required some optimisations given the immediate airport terrain. On a false LOC course . . . the GP course (rate of descent) may not look that unreasonable. The locator NDB (2.1 N.M. before threshold on extended centreline) was decommissioned last summer . . . so you no longer have that reference to tell you it’s on your port/starboard/or behind you when the DME is counting you down to threshold.

The post incident flight check will be performed by the same people who installed and maintain this ILS. Transport Canada and the TSB no longer have flight inspection capabilities . . . unless they contract it from somebody other than Canada’s privately owned air navigation system operator.

Sure hope the CVR and FDR are good and have lots of data points.
And please remember, ILS is a System with many other information inputs . . . not just LOC & GP crosshairs . . . . . . .

RESA, not saying you are wrong but another aircraft flew the backcourse approach twice, the second time becoming visual without reporting any anomalies.

Aterpster,
Thanks, I did see that photo shortly after I put up my last post. It's the most instructive I've seen of the crash site.
Looking at the wreckage, I am amazed that anyone survived. Most probably they did so because they were seated in the very tail. That's where they put the pax on largely-freight flights to YRB (that's what the majority of the flights are anyway). The degree of fragmentation of the aircraft is remarkable. Maybe that's what Rollingthunder means when he says that the wreckage doesn't look right.
One thing's for sure, you don't want to find yourself at low altitude east of the YRB runway unless you're in a helicopter in CAVU conditions.

CYRB First Air 737 crash
 

PLovett

CYRB back course is 17T . . . no GP

Approach is 35T with GP(glidepath)/DME.

Technically, the only correct way he could report 3 N.M. to threshold is on the 35T approach.

A sub-2000m gravel runway in poor weather with up to 13kts of downwind in a 737-200, which most probably has a Flight Manual 10kt tailwind limit (as other early model 737s). I would not class that as a "no difficulties" approach.

Also interesting was the presence of the other aircraft. While the timings are not clear, if an aircraft had gone missing, I would have thought it prudent to hold somewhere out of the way until the whereabouts of the missing aircraft had been resolved. It might have had a radio failure and be attempting further approaches. It would certainly load me up knowing there was another aircraft doing instrument approaches in the opposite direction to mine.

Have heard of false captures but not a false localizer.

http://www.pprune.org/rumours-news/4...ml#post6654152


Looking at top post in the above link,


I can guarantee that it is standard procedure for a crash investigator to check the position of all instruments, knobs, handles, etc in the cockpit. This includes the nav frequencies selected.

CYRB First Air 737 crash
 

Transportation Safety Board of Canada - Welcome

Transportation Safety Board of Canada - Featured Investigations - Aviation - 2011 - A11H0002

RESA, I understand that there is no GP on a backcourse approach but it was the localiser signal that you referred to in your post as being possibly at fault. That is the same signal either for localiser or backcourse.

PLovett

BC 17T has an NDB (YRB) 1.5 N.M. before threshold on centreline.

Sation passage at YRB should put you inside +/- 20-degrees of centreline, so any LOC lock should be very near centreline and not a false capture or false course. If your LF DF doesn't spin before you are a mile from the runway . . . you are likely not heading for the runway centreline . . . ?

The prop jockey landing on 17T had this advantage (albeit with no GP) . . . likely more "aware" because of no GP?

JammedStab

Older Localizers (certain brands) frequently have false capture problems . . . particularly on very long runways as the equipment is being overdriven in order to narrow the course width.

Some older equipment (still in use) employ an antenna system that can partially fail causing both false capture and false course that the executive monitors will not detect.

nuff said . . . not about to give course here . . .

Is it possible they still had 29.92 set as opposed to local qnh?

B732 max tail wind limit 15 kts(AFM:Tkof/Ldg) .Can't find a reference to gravel ops that reduces it.Nicest aeroplane I've ever flown,by far.

How can the wreckage "not look right"? Are you suggesting that somebody has been out there moving things around? If not, what ARE you suggesting exactly? (not having a go, genuinely interested in what you are thinking)

Looking at the maps that have been put up showing the crash site it strikes me that the aircraft's track to the VOR indicated on The map looks very very close to the ILS course.

Is it possible that they had mistakenly selected the VOR frequency rather than the ILS and flew what they thought was the localiser course straight towards the VOR with it's unexpected high ground in the way?

Pure speculation from a non-pilot so feel free to explain why this would or would not be possible.

Probably because I cannot find a VOR there?

"B732 max tail wind limit 15 kts" 10kts is a standard unless negotiated with Boeng (ie pay more money)

There is no VOR approach, but there is a VOR in the vicinity of the impact location.

Capn Bloggs and BOAC,
Pilots flying in the Canadian Arctic of necessity tend to push the envelope routinely, but have the experience to do so in a professional and safe manner. Their excellent safety record, in a challenging environment, speaks for itself.
Rockhound

- tell us more. Jepp do not know of it.

Rock - not QUITE sure why I was addressed in that post, and I see no justification in 'pushing any envelopes' when you may kill yourself and your pax/crew?

Forgetting all about tailwinds, back-courses, front courses, circling etc:

1) The impact was too close in for a 'downwind' (yes, even in TERPS)

2) IF major technical failure is ruled out, what does that leave you with - 'envelope pushing'?

I don't have access to Jepps right now, but the link below shows the location of the VOR.

http://www.ourairports.com/navaids/YRB/Resolute_Bay_VOR-DME_CA/

Thanks, opale4.

Because the YRB VOR DME wasn't relevant to the ILS 35T approach, it does not appear on the AIP or Jeppesen chart. The VOR DME is depicted on the enroute chart.

Check out this report of a GIII accident at KHOU in 2004.

I remember following that one. A very early start, a rushed approach and tracking the VOR instead of the LOC. Confusion about the EFIS presentation of fast/slow and G/s indications. They were supposed to be picking up George H.W. Bush. Two highly experienced pilots made a mistake that's not all that difficult to make.