Originally Posted by aterpster
(Post 9763767)
Perhaps there was an issue with the airplane's DME. Otherwise the LOC Rwy 5 would have been a far better choice. Or, with that slight wind, the ILS 23 would have been an even better choice, no DME required.
Visibility was 10 miles so the approach was legal for any category. Is the SD-330 category B (max speed 135 knots) for circling perhaps?
Originally Posted by aterpster
(Post 9763776)
Also, these are circle-to-land-only minimums (that's why it's VOR-A, not VOR Rwy 05), which have their own set of traps for the unwary. And, the final approach course radial is 31 degrees different than the runway center-line.
All in all, quite the non-precision IAP.
Originally Posted by aterpster
(Post 9763881)
We don't know where the flight came on to the TRACON's radar. Perhaps the position favored least remaining track miles to Runway 5. Presumably, we will find that out, or perhaps someone already has.
http://archive-server.liveatc.net/kc...2017-1030Z.mp3 The audio is not great and it sounds like the VOR-A was requested by the SD-330 crew from the context. As aterpster observed, DME is required for the LOC Rwy 5 but not for the VOR-A.
Originally Posted by Zaphod Beblebrox
(Post 9763696)
I will make this observation, at the risk of over generalizing.... This flight was operated under FAR part 135, (I think), and therefore not subject to the ATP requirement for passenger Part 121 operations in the US.
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Originally Posted by peekay4
(Post 9763973)
1. There's a report that the aircraft struck trees on final approach. Has this been substantiated?
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Originally Posted by peekay4
(Post 9763973)
A couple key questions at this point:
1. There's a report that the aircraft struck trees on final approach. Has this been substantiated? 2. There are witness statements and apparently more than one surveillance video showing the aircraft landing at a "very strange angle". What could be the cause? Sudden gust / windshear? Last minute side-slip? Mechanical trouble? |
Hmm. If there was no impact prior to the threshold, I guess the most "plain" possibility is that the aircraft broke out of clouds significantly high or offset from the runway centerline and impacted while attempting to maneuver back to the centerline? Or alternatively stalled while attempting to go-around, causing a wing drop and subsequent crash.
Those who've seen the videos probably have a good idea of what happened. |
The NTSB is limited by the lack of either a CVR or FDR.
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Originally Posted by peekay4
(Post 9763973)
A couple key questions at this point:
1. There's a report that the aircraft struck trees on final approach. Has this been substantiated? 2. There are witness statements and apparently more than one surveillance video showing the aircraft landing at a "very strange angle". What could be the cause? Sudden gust / windshear? Last minute side-slip? Mechanical trouble? |
Only thought I can add to points already considered is that KCRW is a "tabletop" airport, with a steep upslope rising to meet rwy 5.
A south tailwind could result in an updraft under the approach, that may have interfered with the pilots' planned maneuvering. Picture also shows the landslide that "ate" part of the EMAS. http://www.wvgazettemail.com/apps/pb...=1493510400069 |
Originally Posted by pattern_is_full
(Post 9764200)
Picture also shows the landslide that "ate" part of the EMAS.
https://goo.gl/maps/3YGuCXS3PjF2 |
Yep. Although some of that is the repair work - and raises the question of what effect the on-going repairs (lights? parked equipment?) may have had, sitting right at the runway end. I'm sure no one was probably on the job at 6:53 ayem - but was the site itself a distraction?
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Those gouge marks in the runway surface (video 3) look to be 1 or 2 inches deep which means the aircraft hit pretty damn hard. The marks also evidence a touchdown travelling at an angle of 30deg across the runway centreline so the approach was very far from being stable. The debris field appears to indicate airframe break-up started BEFORE the main body went down the ravine.
Considering that the cloud ceiling was 500' above the runway it is difficult to imagine how a stable approach (even one that busted minimums) could have been mishandled enough to result in crossing the runway at 30 degrees with such a rate of descent. It is quite possible this aircraft was stalled at impact. |
Also, the angle of the gouges is 'opposite" the misalignment angle of the final approach course of the VOR-A approach.
Possible scenario. They got the runway in sight late and by the time they had turned left to align with runway heading they had overshot the runway centerline considerably, which would necessitate continuing left turn back toward the runway, and then a right turn before touchdown to align with runway heading. Ran out of altitude to complete right turn to runway heading, so impacted in bank, while travelling at angle to runway. |
Reminds me of an accident at Newtownards N.I. around 15 years ago where the pilot seeing the runway late (in that case due to limited visibility rather than breaking through low cloud) turned over-sharply towards the runway so that the wing on the inside of the turn stalled with insufficient height to recover.
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1 Attachment(s)
VOR-A final approach course with missed approach fix MACSA and FAA airport diagram.
If they didn't have an operating DME they would have been required to time the approach. |
As long as we're speculating about the operational status of their equipment; If they didn't have an operating localizer receiver, they would have had to take the VOR-A, with a tailwind, and an MDA above the ceiling.
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Doubt they would have had VOR but not LOC. They are usually the same receiver, more or less.
I am not speculating that they did not have an operational DME. I am stating what anyone would have to do to fly the VOR-A without DME whether inoperable or not installed. |
Originally Posted by aterpster
(Post 9764740)
Doubt they would have had VOR but not LOC. They are usually the same receiver, more or less.
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Speculation about which type of approach they were flying...... and how this precipitated the crash is pretty immaterial and will not lead to the 'why'.
Despite this aircraft being flown by two capable guys who were both visual with the field from 500' down to the runway they crashed hard at a steep crossing angle to the centreline. That strongly suggests that the aircraft was not under control when it hit the runway - This is where the focus of the investigation will lie. |
Originally Posted by Magplug
(Post 9764759)
they crashed hard at a steep crossing angle to the centreline. That strongly suggests that the aircraft was not under control when it hit the runway -.
Originally Posted by Magplug
(Post 9764759)
Speculation about which type of approach they were flying...... and how this precipitated the crash is pretty immaterial
As for why they chose that approach, no, that's not terribly relevant, but it's certainly something pilots would tend to wonder. |
Circling Approach MDA 800 AGL
KCRW 051054Z 23003KT 10SM FEW001 OVC005 14/13 A2941 RMK AO2 SLP952 VLY FG T01440133= |
Originally Posted by Magplug
(Post 9764759)
Speculation about which type of approach they were flying...... and how this precipitated the crash is pretty immaterial and will not lead to the 'why'.
The question is why would they fly that approach to circling mins if the LOC Rwy 5 with runway alignment and lower mins was available? They were told to expect the LOC Rwy 5 on initial contact with CRW approach control.
Originally Posted by gearlever
(Post 9764801)
Circling Approach MDA 800 AGL
Again, here is the VOR-A chart: http://155.178.201.160/d-tpp/1705/00852VA.PDF |
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