AA 1897 SAT-PHX Divert to ELP for Hail Damage

[Coochycool]

Thanks for posting. That's the first image I've seen which makes the nature of the damage trully apparent. I think what we're looking at here is some residual inner layers of the radome which have been pushed inwards. Earlier images with poorer contrast had led me to believe that the radome had in fact been entirely erased and we were looking at an exposed forward pressure bulkhead. Merely humble SLF here, so I wonder if others more learned on here can advise whether there have been known instances of aircraft losses under such circumstances, and whether forward bulkheads are ever tested or rated with this scenario in mind?

[tdracer]

Originally Posted by Coochycool

. Merely humble SLF here, so I wonder if others more learned on here can advise whether there have been known instances of aircraft losses under such circumstances, and whether forward bulkheads are ever tested or rated with this scenario in mind?

Southern Airways DC-9 - both engines quit due to ingesting massive amounts of hail:
https://en.wikipedia.org/wiki/Southe...ays_Flight_242

[lomapaseo]

..... so I wonder if others more learned on here can advise whether there have been known instances of aircraft losses under such circumstances, and whether forward bulkheads are ever tested or rated with this scenario in mind?

The greater risk is from a large bird. They are qualified to absorb a strike at 250 kts

[Centaurus]

Be interesting to know if the disrupted airflow from the shattered radome affected the airspeed and altimeter readings.

[Airbubba]

Originally Posted by Airbubba

You can see where they may have thought there was a break in the line of weather over New Mexico and then hit a hail shaft in the 'clear' area.

Here's an animation of AA 1897 navigating through the line of weather:

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[SLF3]

SLF: Doesn't look like they could see much. How do you land in a situation like this? Presumably the auto-landing system will get you on the ground, but does it also keep you in a straight line while you decelerate?

[wiedehopf]

The tracks of some other aircraft tackling the same storm:

[Reluctant Bus Driver]

The aircraft in question was one of the older America West Basic A319's. Unlike the enhanced aircraft the radar is not nearly as good. Its entirely possible it painted returns that looked reasonable to the crew. The enhanced radars are far better and could theoretically have prevented this.

[SeenItAll]

Originally Posted by wiedehopf

The tracks of some other aircraft tackling the same storm:

the only real smart one looks like UAL1521. But again, I wasn't there (thankfully) so really don't know.

[llondel]

Originally Posted by tdracer

Southern Airways DC-9 - both engines quit due to ingesting massive amounts of hail:
https://en.wikipedia.org/wiki/Southe...ays_Flight_242

I thought that was more because they suffered compressor stalls but didn't (or couldn't) throttle back to let the engines recover. ISTR that ATC was pushing them to climb so they kept trying to get the engines to produce more power until the compressor blades all fell off.

[MarkerInbound]

Originally Posted by SLF3

SLF: Doesn't look like they could see much. How do you land in a situation like this? Presumably the auto-landing system will get you on the ground, but does it also keep you in a straight line while you decelerate?

Yes, it will continue to track the localizer during the rollout. You have to disconnect the autopilot to turn off the runway.

[wiedehopf]

Originally Posted by SeenItAll

the only real smart one looks like UAL1521. But again, I wasn't there (thankfully) so really don't know.

i've attempted an overlay with data from https://gis.ncdc.noaa.gov/maps/ncei/radar but at high level the cloud temperature chart probably gives a better picture of the situation.
anyway i'll post it and maybe i just did the overlay wrong but i don't think so.

[tdracer]

Originally Posted by llondel

I thought that was more because they suffered compressor stalls but didn't (or couldn't) throttle back to let the engines recover. ISTR that ATC was pushing them to climb so they kept trying to get the engines to produce more power until the compressor blades all fell off.

Going from memory here, but IIRC the compressor bleeds became plugged with the massive amount of ice - which then lead to the compressor stalls when they tried to accel the engines. However I also seem to recall that there was compressor blade tip curl consistent with ingesting so much incompressible water/ice - the blade damage then contributed to the compressor and inability to clear the stall. Eventually blades started coming apart and it was game over.
Sadly, they were within gliding range of an airport when they lost all power, but for some reason they then temporarily lost battery power (including the radios) and without guidance they turned the wrong way - by the time they got the radio back it was too late - they'd lost too much altitude.

[Airbubba]

Originally Posted by tdracer

Going from memory here, but IIRC the compressor bleeds became plugged with the massive amount of ice - which then lead to the compressor stalls when they tried to accel the engines.

Good memory! Here's the NTSB report:

https://www.ntsb.gov/investigations/...ts/AAR7803.pdf

Years ago I sat through Archie Trammell's analysis of this 1977 mishap and the role of weather radar in the decision to penetrate the line of storms.

[aterpster]

Originally Posted by Airbubba

Years ago I sat through Archie Trammell's analysis of this 1977 mishap and the role of weather radar in the decision to penetrate the line of storms.

That's why it's called weather avoidance radar. Also, the radar set on that airplane was likely not very good.

[Airbubba]

An update on the repairs:

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[BAengineer]

9 mechanics to change 2 windows and a nose cone in 3 days... methinks someone is milking the overtime....

[msbbarratt]

Originally Posted by BAengineer

9 mechanics to change 2 windows and a nose cone in 3 days... methinks someone is milking the overtime....

There's a lot of buffing out to be done...

[aterpster]

Originally Posted by SLF3

Presumably the auto-landing system will get you on the ground, but does it also keep you in a straight line while you decelerate?

Yes, but it won't taxi you off the runway.

[JammedStab]

Maybe it is best to just go around the whole line instead of penetrating it. This was my flight a little while back. No penetration, no issues. Missed seeing the Grand Canyon though.