Loss of engine cover on Southwest Boeing 737-800 prompts FAA investigation
Yes, it was a Flaps Up Landing.
I wonder what the Groundspeed was - especially in Denver!! Anybody to retrieve Vref? What was the winds and temperatures at that time?
I wonder what the Groundspeed was - especially in Denver!! Anybody to retrieve Vref? What was the winds and temperatures at that time?
VREF 40 at 65T is around 140kts and the checklist suggests VREF 40+ 40kts for trailing edge flaps up (180kts) or 55kts for all flaps up. So flying plus 5kts gives a rather tasty 200kts approach speed!
(Just figures based on a nearly max weight landing without knowing any details other than looking up Denver and seeing it is 5500’ ish elevation.)
EDIT: Figures are for a 737-800, 15*, at home base which is 680’ elevation. So speeds for Denver will be even higher, probably!
My figures for All Flaps up landing, Max manual braking come to just over 6000’.
Last edited by Jump Complete; 8th Apr 2024 at 09:32.
Based on the approach speed alone I would think you are looking at a serious amount of runway required. There was a headwind but ISA+10/15 at 5500AMSL is going to add all that back in plus a bit. To be on the safe side you’d plan on losing a reverser as you don’t know with the cowl damage if it will deploy.
Would be surprised if brakes on was less than 200kts groundspeed. Long time since I flew the 737 but that’s going to need a lot of the runway assuming the brakes can take that level of input and still slow you down...
Would be surprised if brakes on was less than 200kts groundspeed. Long time since I flew the 737 but that’s going to need a lot of the runway assuming the brakes can take that level of input and still slow you down...
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Could this be related to the comment by BFSGrad about the wind and runway length? Perhaps the pilot had to use the reversers.
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Well, if the cowling hit the flaps, maybe they didn't or could use them to land, came in hot and still needed reversers? I don't see the slats deployed in the video of the landing from inside the plane.
With a mass range of 110-170lbs we then get 177-208KN +5 KN wind we can expect the landing was at 182-213KN IAS
Assumed Wind - Actual Wind still unknown?
What is the Altitude based Ground Speed derived from 182-213KN?
Flightaware shows a Speed of ~210KN, and before touchdown one 184KN mark. I dont know what the speed value means on Flightaware.
Edit:
OK, FR24 showed Groundspeed of 211KN the seconds before touchdown, That is something!!!
Tyre Limit is 190KN?
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Reported to be N8668A (reg not visible on videos) On takeoff right hand eng#2 right hand aft cowl door came loose first, opened and flapping around … pilots only know after CCW and pax report…pilots think inner flap hit … return for overweight and no flaps landing, fuel 22.9 with 6 crew and 135+2 pax … change from rwy 25 to 26 then 34L …on landing left hand cowl visibly opened too… both doors flapping around and shredding, only small pieces remain…
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No surprise that as SLF/attorney I'm keeping a big whole runway length out of the pilots talking about flying here. But I will momentarily divert the flying talk to note that at least one main media outlet has not piled onto the ongoing Boeing crisis in reporting on this incident. This morning on CNBC Squawk on the Street the reporting was very factual; incident aircraft manufactured in 2015 and not a MAX, FAA investigating, just the facts, sir or madam.
Having had a think about it, this is quite a nasty problem to be handed. Enough damage to require a very non-standard landing, possibly > MLW, plus time pressure as the cowls are coming apart and who knows what the next loose bit is going to hit (it’s already done for the flaps and slats), which restricts the options to a land ASAP.
Some of the things that would be going through my mind are: high DA and with the resultant GS, that’s 1,100fpm to stay on the glide slope, so a flare is definitely required to avoid a crash, but at the same time a float will use a lot of runway. Which runway? The long one or the into-wind one? Will the brakes take it? They are certified to some fairly extreme requirements but does a flapless landing at high altitude and high weight fall within them? Don’t want to get brake fade at 100kts when the reversers are starting to lose their effectiveness, so maybe a lower brake setting and let the reverse take more of a share of the energy removal? Will they catch fire soon afterwards or can we limit that? Lots of stuff to think about in a very short time...
Some of the things that would be going through my mind are: high DA and with the resultant GS, that’s 1,100fpm to stay on the glide slope, so a flare is definitely required to avoid a crash, but at the same time a float will use a lot of runway. Which runway? The long one or the into-wind one? Will the brakes take it? They are certified to some fairly extreme requirements but does a flapless landing at high altitude and high weight fall within them? Don’t want to get brake fade at 100kts when the reversers are starting to lose their effectiveness, so maybe a lower brake setting and let the reverse take more of a share of the energy removal? Will they catch fire soon afterwards or can we limit that? Lots of stuff to think about in a very short time...
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Having had a think about it, this is quite a nasty problem to be handed. Enough damage to require a very non-standard landing, possibly > MLW, plus time pressure as the cowls are coming apart and who knows what the next loose bit is going to hit (it’s already done for the flaps and slats), which restricts the options to a land ASAP.
Some of the things that would be going through my mind are: high DA and with the resultant GS, that’s 1,100fpm to stay on the glide slope, so a flare is definitely required to avoid a crash, but at the same time a float will use a lot of runway. Which runway? The long one or the into-wind one? Will the brakes take it? They are certified to some fairly extreme requirements but does a flapless landing at high altitude and high weight fall within them? Don’t want to get brake fade at 100kts when the reversers are starting to lose their effectiveness, so maybe a lower brake setting and let the reverse take more of a share of the energy removal? Will they catch fire soon afterwards or can we limit that? Lots of stuff to think about in a very short time...
Some of the things that would be going through my mind are: high DA and with the resultant GS, that’s 1,100fpm to stay on the glide slope, so a flare is definitely required to avoid a crash, but at the same time a float will use a lot of runway. Which runway? The long one or the into-wind one? Will the brakes take it? They are certified to some fairly extreme requirements but does a flapless landing at high altitude and high weight fall within them? Don’t want to get brake fade at 100kts when the reversers are starting to lose their effectiveness, so maybe a lower brake setting and let the reverse take more of a share of the energy removal? Will they catch fire soon afterwards or can we limit that? Lots of stuff to think about in a very short time...
Okay, here's another example. Write the algorithm which solves for all the variables and decisions noted by FullWings. I would say, "I'll wait" but I think I'd be waiting a long, long time.
And this really higher than usual speed squeezes the timing. How does it affect the pitch? probably not that much cause you are relatively same percentage above minimum speed?
How high do you flare?
Will you go below G/S to save some distance on short runways? (not a factor here,i suppose)
It did not appear to have hit the flaps - the outboard cover was still attached after takeoff and was entirely above the wing and the inboard cover spent its time on the loose over the wing as well. The outboard cover appears to have banged up the top of the nearby slat, but the dents on top aren't as bad as some I've seen from hail damage.
I'd go for excessive caution, but given the entirely unknown situation and being unable to observe beneath the wing, with the option of the long runway they had, it was a reasonable choice to take it.
Most likely the tires are heading for a retread and the brakes will need a look; both a small price vs the potential cost of damage to the horizontal stab if a cover let loose at a higher AoA typical during landing.
I'd go for excessive caution, but given the entirely unknown situation and being unable to observe beneath the wing, with the option of the long runway they had, it was a reasonable choice to take it.
Most likely the tires are heading for a retread and the brakes will need a look; both a small price vs the potential cost of damage to the horizontal stab if a cover let loose at a higher AoA typical during landing.
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Flaps and slats work off the same lever. Can't speak for the 737, but typically slats are first or in conjunction with some flaps.
A question re. Brake energy and V1.
What is the max V1 speed that this 737 could have at max weight?
The brakes are certified to work for a Max weight rejected take off at V1 with Max braking. I suspect the max V1 will be around 170 kts. So this aircraft landed at a speed around 200 kts., at less than max weight, with over 12000ft of runway to stop in. I doubt the brake temps were over limits.
Also I don't think the altitude will affect the IAS but the TAS and ground speed will be higher.
I've been out of flying for over 10 years so maybe I've forgotten something.
What is the max V1 speed that this 737 could have at max weight?
The brakes are certified to work for a Max weight rejected take off at V1 with Max braking. I suspect the max V1 will be around 170 kts. So this aircraft landed at a speed around 200 kts., at less than max weight, with over 12000ft of runway to stop in. I doubt the brake temps were over limits.
Also I don't think the altitude will affect the IAS but the TAS and ground speed will be higher.
I've been out of flying for over 10 years so maybe I've forgotten something.