I don't think i would trust those numbers. I highly doubt a Boeing 767 - with any flaps - could stay airborne and flying below 120 kts.....never mind 109 kts.
At the 120kts & 109kts groundspeed you still have potential for 15kts gusting given in the current metar at the time, which means component right on the beak raising airspeed to 135 kts & 124 kts respectively. Coming up on the runway however (maybe different story?) could be the airspeed still slowing somewhat below the groundspeeds shown above, given the veering potential in the area (from the metar issued immediately following this incident).
altiplano wrote: ↑Mon Nov 25, 2024 11:40 pm
I also heard that one reverser was MEL'd and they didn't have speedbrakes on landing, either failed to deploy, weren't manually selected, or just didn't work.
If they had an inop reverser as well, things are starting to add up. How easy is it to go to Seattle on 23000 pounds of fuel with a restriction FL200 and an airspeed restriction? Perhaps unknown due to the unknown nature of the fault. But is it obviously easy or potentially marginal?
And what was the reason for 08R closure. Could it have been made available in 30 minutes?
I don't think i would trust those numbers. I highly doubt a Boeing 767 - with any flaps - could stay airborne and flying below 120 kts.....never mind 109 kts.
At the 120kts & 109kts groundspeed you still have potential for 15kts gusting given in the current metar at the time, which means component right on the beak raising airspeed to 135 kts & 124 kts respectively. Coming up on the runway however (maybe different story?) could be the airspeed still slowing somewhat below the groundspeeds shown above, given the veering potential in the area (from the metar issued immediately following this incident).
altiplano wrote: ↑Mon Nov 25, 2024 11:40 pm
I also heard that one reverser was MEL'd and they didn't have speedbrakes on landing, either failed to deploy, weren't manually selected, or just didn't work.
If they had an inop reverser as well, things are starting to add up. How easy is it to go to Seattle on 23000 pounds of fuel with a restriction FL200 and an airspeed restriction? Perhaps unknown due to the unknown nature of the fault. But is it obviously easy or potentially marginal?
And what was the reason for 08R closure. Could it have been made available in 30 minutes?
The grapevine said that SEA was experiencing windshear warnings at the time. Don't know if thats true or not right now.
altiplano wrote: ↑Mon Nov 25, 2024 11:40 pm
I also heard that one reverser was MEL'd and they didn't have speedbrakes on landing, either failed to deploy, weren't manually selected, or just didn't work.
If they had an inop reverser as well, things are starting to add up. How easy is it to go to Seattle on 23000 pounds of fuel with a restriction FL200 and an airspeed restriction? Perhaps unknown due to the unknown nature of the fault. But is it obviously easy or potentially marginal?
And what was the reason for 08R closure. Could it have been made available in 30 minutes?
The grapevine said that SEA was experiencing windshear warnings at the time. Don't know if thats true or not right now.
With how quick they ran the checklist and then straight into the approach, I doubt that they even looked into SEA
---------- ADS -----------
Complex systems won’t survive the competence crisis
digits_ wrote: ↑Wed Nov 20, 2024 8:58 am
The recording said leading edge flaps trouble. Could this have affected spoilers/speedbrake deployment?
No, but an air/ground logic issue which someone mentioned, definitely would. If the system erroneously considered the aircraft airborne you'd have no ground spoilers, greatly increasing ground roll - like, 60% more - and no reversers (inhibited in "air" mode). The fact that not all the spoiler panels appear not to have deployed supports this theory. The recent wheel assembly maintenance work also raises a flag, it's been years since I flew the 767 but I dimly recall some weight-on-wheels switches around there.
A slightly deep landing doesn't have you going off the end at 100 knots. On the unlucky day when you're coming in very fast and heavy, thus much longer than normal landing roll, no lift dump + no reverse sure could.
Of course, if I'm correct we wouldn't be able to throw shade at the crew for not going around, so what fun is that?
There are independent tilt sensors on each main gear truck and a sensor in the nose too for air/ground logic. I don't recall the specifics on the system though.
I also heard that one reverser was MEL'd and they didn't have speedbrakes on landing, either failed to deploy, weren't manually selected, or just didn't work.
The air/ground sensor in the nose gear is for takeoff config warning.
I think we are all assuming that the spoilers, brakes, and reversers were not working. If the air/ground system did have a fault - they would get an "AIR/GRD SYS" EICAS message. In that case - the book says (the one I'm looking at)
* one or both T/R's inop
* Auto brakes inop
* Auto Speedbrake inoperative. When deployed manually, spoiler capability is reduced.
[The ground spoiler on each wing will not deploy.]
I can't see them not telling the tower.
So what?....they just landed and went along for the ride forgetting that the auto systems don't work?
They (pilots) can do 150-155kts airspeed to aim for touchdown but a cooler WNW 7-10kt air parcel encountered somewhere at around 6miles out (here begins to register at airport half hour after overrun) steadily nudges groundspeed higher late-glideslope maybe without warning (among emergency distractions), just before the East component of 10kts (and gusting) farther down rwy … prolongs float. (Starts out on glide slope as light decreased performance shear but at those speeds reverts to an increased performance event by about halfway down rwy.)
The flight radar numbers presented above seem to show it nose low past theshold at 25ft AGL but then maybe goes 50ft AGL when cockpit altimeter higher up in nose up flair ? …floating a long way, finally shows 0-AGL where at spectacular stoppage track in overrun zone.
The cyclone close by behind you … and ene 10kts (tower/metar) given for this rwy/time, one would expect even slower GS than airspeed in reaching threshold (even stronger headwind higher up) but instead minus five or more reverse component … likely one reason GS rises to “173” right there. Q: So at which location in this situation on this runway is too late for safe go around ? … right away ? .. before halfway ? ..
Q: So at which location in this situation on this runway is too late for safe go around ? … right away ? .. before halfway ? ..
From the chart I'm looking at with good reported braking action and depending on configuration/weight - they needed around 6500' (8900' runway) or more to stop (assuming reverse and manual braking worked) - a go around decision has to be made pretty quick.
Q: So at which location in this situation on this runway is too late for safe go around ? … right away ? .. before halfway ? ..
From the chart I'm looking at with good reported braking action and depending on configuration/weight - they needed around 6500' (8900' runway) or more to stop (assuming reverse and manual braking worked) - a go around decision has to be made pretty quick.
In addition to an expected roughly 30kts component lost rather quickly (as descent also more-rapid than a normal one) from on base down thru to about mid glidedlope (see valid gfa 30-40kts ESE in area) there was that additional groundspeed increase (airspeed instead of higher than groundspeed looks like would have been at least 5ks lower than GS by about 1/4 final) within emergency’s intention possibly to land on first try. Achieving that goal might have looked on track immediately prior-to or even during the mild low level unpredictable shear (an unexpected decreased performance) still persisting just ahead of this tdz despite a contrary anemometer indication evident for CYVR centre-field.
As an option, yes, “pretty quick” would have to be the case; here the window for safe go-around is perhaps also lost ‘very quick’ from the moment where it could/may have been realized.
pdw wrote: ↑Fri Nov 22, 2024 6:39 am
At the 120kts & 109kts groundspeed you still had potential for 15kts gusting given in the current metar at the time, which means with that component right on the beak raising airspeed ….(edit) back up higher
PDW…. YOUR BACK!!!!’k
He blows in with the wind!
IMO this is a made-easier opportunity to see math of lighter shear affecting stability more with this type (10-15kts faster IAS than normal) approach, the mild back and forth (lighter/seesaw) shearing experienced across this landing area during a ‘pan pan’.
The “comparison aircraft” data of the previous hour’s approach (from page one posted by Nauclerus) shows 39kt difference in groundspeeds about 1/2 mile final between two similar size airliners, yet airspeed difference is only about 50 percent of their groundspeed difference. Approx 2:1 GS/AS difference ratio here can identify magnitude of affecting shear after-the-fact (not so predictable in advance), which is on account of the freezing mountain surface air’s flow strengthening downslope more aggressively out of higher terrain north/northeast of CYVR toward the deepening (bomb cyclone) low pressure southwest.
It looks like after a half mile final to up-to two miles past threshold (about a one minute transition) could have experienced up to about 20kts of increased performance shear (total possible between the “5Kt WNW” and a 15kt East gust) just before actual touchdown.
pdw wrote: ↑Fri Nov 22, 2024 6:39 am
At the 120kts & 109kts groundspeed you still have potential for 15kts gusting given in the current metar at the time, which means component right on the beak raising airspeed to 135 kts & 124 kts respectively. Coming up on the runway however (maybe different story?) could be the airspeed still slowing somewhat below the groundspeeds shown above, given the veering potential in the area (from the metar issued immediately following this incident).
PDW…. YOUR BACK!!!!’
He blows in with the wind!
Like a Garrison Irish Red Ale fart on the Halifax Waterfront
IMO this is a made-easier opportunity to see math of lighter shear affecting stability more with this type (10-15kts faster IAS than normal) approach, the mild back and forth (lighter/seesaw) shearing experienced across this landing area during a ‘pan pan’.
The “comparison aircraft” data of the previous hour’s approach (from page one posted by Nauclerus) shows 39kt difference in groundspeeds about 1/2 mile final between two similar size airliners, yet airspeed difference is only about 50 percent of their groundspeed difference. Approx 2:1 GS/AS difference ratio here can identify magnitude of affecting shear after-the-fact (not so predictable in advance), which is on account of the freezing mountain surface air’s flow strengthening downslope more aggressively out of higher terrain north/northeast of CYVR toward the deepening (bomb cyclone) low pressure southwest.
It looks like after a half mile final to up-to two miles past threshold (about a one minute transition) could have experienced up to about 20kts of increased performance shear (total possible between the “5Kt WNW” and a 15kt East gust) just before actual touchdown.
Umm....OK.
Lets look at something more interesting! She came out pretty good considering what it went through.....Rumor mill says it suffered a 6G deceleration and the list of NDT is long. Now...I have not confirmed any of that - but in the wake of how fast they were going - and the distance it took to stop - I would not be surprised if that was true.
And finally the LH gear. For everyone wondering about air/ground switches. The switches in the 767 are internal to the tilt actuators. You can see the cannon plug here and both it and the wiring appear intact. If it was an air/ground issue....I don't think it's because of this (from the previous taxiway excursion.)
By 1/4 final the GS surged ahead of AS here, while AS was already being managed higher intentionally, and probably gains 5kts more AS inadvertently while adhering to g-slope throughout the decreased performance shearing (increasing speed) encounter. It seems the creep-up to higher energy is very subtle still though, despite seeing the 35kt/25-percent higher GS than the “comparison” aircraft’s approach speed .. as per earlier discussion.
Edit .. next we may need to have a closer look at what low level shear zone eddies are all about …. whether such phenomenon could have applied here at this inversion situation …
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Last edited by pdw on Wed Jan 15, 2025 8:18 am, edited 1 time in total.
pdw wrote: ↑Wed Jan 01, 2025 12:36 pm
By 1/4 final the GS surged ahead of AS here, while AS was already being managed higher intentionally, and probably gains 5kts more AS inadvertently while adhering to g-slope throughout the decreased performance shearing (increasing speed) encounter. It seems the creep-up to higher energy is very subtle still though, despite seeing the 35kt/25-percent higher GS than the “comparison” aircraft’s approach speed .. as per earlier discussion.
Old fella wrote: ↑Thu Dec 19, 2024 7:34 pm
Like a Garrison Irish Red Ale fart on the Halifax Waterfront
Garrison in YHZ is a nice visit … you first endure some dehydration awaiting the post-tour flight(s) of beer. Then you get up for the walk along the pier ….
Now I'm a broken man on a Halifax pier
The last of Barrett's privateers
If I read this correctly, no reverse and no brakes. Could there be an air/ground sensor issue?
C-GAZI, a Cargojet Airways Limited Boeing 767-338 departed John C. Munro Hamilton
International Airport (CYHM), ON, on flight CJT2387, under instrument flight rules, to Vancouver
International Airport (CYVR), BC, with 2 flight crew members and 1 jumpseater on board. During
the descent into CYVR, the crew received a slat asymmetry warning. The crew leveled off, notified
air traffic control, and declared a PAN PAN. The crew then completed the applicable checklist and
prepared for a faster than normal approach and landing speed due to the slat issue. CYVR aircraft
rescue and firefighting (ARFF) crews were placed on standby. After touching down, the crew
applied the brakes and pulled the thrust reverse handles however, neither engaged. The aircraft
continued along Runway 08L, and departed the runway end at approximately 120kts. The aircraft
collided with numerous approach lights and sunk into the soft muddy ground. The airplane came to
a stop approximately 1250 feet past the end of the paved surface. The crew declared a MAYDAY
and completed the shutdown checklist. The crew and jumpseater egressed with the assistance of
ARFF personnel. There were no injuries. The aircraft was substantially damaged.
The aircraft was recovered from the muddy ground 2 days later. An aircraft damage assessment is
ongoing by the operator. CYVR has repaired the lighting system.
