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-   -   DAL1889 Diverts, Hail Damage (https://www.pprune.org/rumours-news/565836-dal1889-diverts-hail-damage.html)

Subphase 8th Aug 2015 04:16

DAL1889 Diverts, Hail Damage
 
Delta 1889 BOS-SLC diverts to DEN after flying through hail storm.

Tweet from passenger showing damage to front of the plane:
https://twitter.com/rwessman/status/629852479547531268

Story:
http://abcnews.go.com/US/delta-plane...ry?id=32964286

http://i.imgur.com/fvb276P.jpg

jmmoric 8th Aug 2015 17:11

Wow, you get some nasty weather over there :ooh:

Pontius Navigator 8th Aug 2015 20:38

Extraordinary nose and Windows damaged and engine and wing pristine.

Orestes 8th Aug 2015 20:51

Even if the engines look pristine, a full inspection of the fan, and a borescope inspection of the compressor section are in order.

RAT 5 8th Aug 2015 21:01

I would like to hear from the crew their advice on making a successful landing and taxi in. Did they make an autoland etc? We can all learn something.

Iron Bar 8th Aug 2015 21:48

Sure can, avoid thunderstorms.

B737900er 8th Aug 2015 22:13

Thats another Delta aircraft completely :mad: by flying through a TS.

JRBarrett 8th Aug 2015 22:24

At least some of the news reports indicated that the aircraft "flew through" a thunderstorm, but looking at at the Flightaware track of this flight, it appears they did not fly through any cells. They diverted along the south side of a line of level 6 storms extending from northeastern Colorado into Kansas and Nebraska.

Not far enough south evidently. Intense hail is a real possibility beneath the anvils of supercell thunderstorms - even many miles from the main core of the cells.

underfire 8th Aug 2015 23:19

Rat, According to the ATC traffic, the pilots requested autoland...

pattern_is_full 9th Aug 2015 03:07

Is that a hailstone actually embedded in the dent in the crunched radome? I can't think of any part of the radar kit that normally looks like a rock.

They do (very rarely) get that big in our Great Plains supercells. Largest actually documented (so far) was about 8"/200mm, even after some melting before recovery.

NOAA - National Oceanic and Atmospheric Administration - Monitoring & Understanding Our Changing Planet

As someone who lives in Denver, I can attest that it is quite common in this area to get hail well outside the anvil of one of these beasts - even to the extent that the hail "curtains" are lit up by the westering sun and produce "hailbows."

http://myzone.saferetirementst.netdn...302.jpg?135282

Now, that's at ground level - I have no idea what the updrafts can spit out, and how far, at cruise level.

Just flew into Denver today (as pax) and we were dodging supercells that towered above us even at FL360.

As to the apparent disparity in damage - well, glass is glass, and I'm betting most of the paint removal on the radome was simply the thin aerodynamic shell flexing under the impacts and popping the paint loose.

Capt Claret 9th Aug 2015 04:22

Typical of media reporting, the aircraft was reported, on the video I saw, as a 747. And it was brought in on the skill of the tower controllers. :ugh:

7478ti 9th Aug 2015 05:56

Still lots to learn about TRW deviations and Radars
 
Another fortunate successful diversion landing after a hail encounter. Thankfully we also have good autoland systems. But apparently, there is still more to learn about WX deviations, TRWs, radar characteristics, and radar performance. Even some of the the most recent WXRs, in the latest production jets, still have known "issues", and require care in their use. Anybody know which WXR they were using on this A320?

[Ref: Hail encounters... from Southern 242; DC-9-31; N1335U; executed a forced landing on a highway in New Hope, Georgia, United States after suffering hail damage and losing thrust on both engines in a severe thunderstorm on April 4, 1977, ....to the more recent B747-400 N664US "Spirit of Beijing" crossing the NoPac, into Korea].

speedbird_481_papa 9th Aug 2015 07:12

Pattern_Is_Full

Looking at the amount of damage that radome has suffered I would say that what you can see is actually the face of the radar dish itself.

Have a look at this picture of an a320 undergoing a major maintenance check. With the nose lifted up to allow access to the radar and look at the protector strips (not sure of the exact technical name sorry, but thats what they're for :}) of the bottom one which is exactly in the middle at the top of the radome on this picture, and compare them to how much they have been bent and warped in the damaged photo.

http://i1210.photobucket.com/albums/...r/IMG_3089.jpg


It looks to me by the ammount that these have been bent that the radome has actually been punctured allowing access to the radar dish.

Regards

Speedbird

ACMS 9th Aug 2015 08:18

I'm surprised they parked at a terminal gate in full view of the public.

Not a good look.

A remote gate may have been a better idea.....

b1lanc 9th Aug 2015 10:42

According to the same guy that took the picture, he referenced a 'sort of hole' above the engine where lightning struck.

Delta Airlines flight from Boston lands in Denver after hail damage | Fox News

pattern_is_full 9th Aug 2015 15:01

Speedbird - I think you're correct.

Avionker 9th Aug 2015 15:12

Speedbird

They are lightning diverter strips, or that is what I have always known them as anyway. I also suspect that you are correct, and that the radome has been completely punched through and the scanner is visible.

misd-agin 9th Aug 2015 16:47

Radome depression has a nice circle on it. Radome pushed back into antennae would be my guess. Hole shows the antennae.

silvertate 9th Aug 2015 18:11

I think the hail-damage on the Easy 737 was worse. Any images of the leading edges on this one?

http://i680.photobucket.com/albums/v...aildamage3.jpg

tdracer 9th Aug 2015 18:35


Any images of the leading edges on this one?
If you look at the wing and inlets in the first photo - there isn't any obvious damage - maybe some small dents, but nothing like that Easyjet stab... I'm actually a bit surprised there isn't more visible damage to the wing and inlet leading edges.
I grew up in Southeastern Colorado - golf ball size hail was not particularly uncommon. And while I personally never saw anything much bigger than golf ball size, buddies experienced baseball size.

tubby linton 9th Aug 2015 18:50

This site has some interesting graphics..Stu Ostro's Meteorology Blog : Meteorological analysis of flight diverted by hail damage | Weather Underground

Vulcancruiser 9th Aug 2015 19:20

hail damage..........
 
ok according to some media that seemed to know what was up......they said they flew this bird BETWEEN two level 6 supercells that closed in on them faster than expected. Another commercial machine also got rocked around but evidently escaped the bigger hail.........and in a weird quirk of fate the pax in the back were watching on some of the laptops as they hit the cells, they had better WIFI info than the pilots did.............

underfire 9th Aug 2015 21:17

Just a question, the radar appears destroyed, doesnt this couple with the autoland?

tubby linton 9th Aug 2015 21:20

Underfire, there is no connection between the two systems.

Chris Scott 9th Aug 2015 22:45

I'm with Pontius Navigator and others on this one: the images available here show little or no sign of damage to the starb'd engine intake or wing L/E. Very odd, but we await better pictures.

Re the nose cone, experience suggests that once the paint and surface of the composite is breached, and the honeycomb underneath exposed (and maybe saturated), the structure is too fragile to withstand the dynamic pressure at cruise IAS. Hence it has collapsed like a ping-pong ball and into the radar antenna.

I wonder if they opened one of the D/V windows for the landing, neither of which look damaged. (That would require cabin depressurisation, of course.)

SaturnV 10th Aug 2015 03:48

From a report of the audio clip, don't have a link to the clip itself,

"Apparently Tower said they were operating with "normal operating bright" and asked the pilots if they wanted the lights brighter since they had problems to see forward.

"Pilots reported the front windshields were severely damaged but they could see at the sides."
________________
Thanks Tub for the link to the radar. imagery In trying to thread through the eye of a needle, they found that the eye had become an explosively developing supercell when they reached it. As it happened, they appear to have flown through the worst part at the worst time.

After a Delta 747, N664US, was severely damaged by hail over China in June, it was subsequently sent to the graveyard.

http://media.bizj.us/view/img/6333201/unknown-11.jpg

Other images here:
Hail pummels Delta's N664US Boeing 747; NWA's "Spirit of Beijing" may face scrapyard (Photos) - Minneapolis / St. Paul Business Journal

NSEU 10th Aug 2015 04:54


Just a question, the radar appears destroyed, doesnt this couple with the autoland?
On some aircraft types, including the A320, the (ILS) Instrument Landing System has antennas behind the radome, so there exists the potential for both radar and autoland to be inoperative if the radome suffered enough damage.

Also, some aircraft have a metallic strip stuck to the inside of the curved radome surface which focusses/concentrates the ILS beam (from the groundstation). Google revealed that in one case, a missing director/reflector strip contributed to an air incident.

Rgds
NSEU

JSmithDTV 10th Aug 2015 09:30

Surely they must've tested the ILS prior to an ILS landing?

Does anyone have more details here? What altitude were they at when the hail hit... cruising I assume?

Why were Delta trying to fly between massive cells? I thought the US airlines were more prudent about flying through large storm cells...

JSmith

SaturnV 10th Aug 2015 11:09

JSmith, the Flightaware log (roughly one+ minute increments) indicates 34,000 feet and 411 knots.

The planned routing on Flightaware had them skirting the south edge of the thunderstorm complex east of Denver, rather than going to the north of it, the latter being a more direct route into Salt Lake. Perhaps, while enroute, the thunderstorms developed where they didn't quite expect.

NSEU 10th Aug 2015 11:57


Surely they must've tested the ILS prior to an ILS landing?
And if the tests fail? Do they not land? :}

I'm sure there are all kinds of very unlikely scenarios. e.g. the radar antenna plate breaking off and sitting in front of the loc and G/S antennas. In this case, perhaps there would be too much shielding for the aircraft's ILS antennas to get a strong enough signal for the entire length of the glidepath and rollout?

I'm not familiar with the A320. How does the A320 handle loss of ILS signals (display pointers removed? flags?)? How does the system handle slightly or greatly disagreeing commands (between ILS systems). Whatever, I assume the crew, in most circumstances, would be able to determine if the signals are valid (i.e. by the aircraft telling them so and by manual periodic height/distance-from-threshold crosschecks).

The ILS antenna can be seen in that photo of the aircraft in the hangar on the previous page. The item which looks like a bathroom towel rail below the radar antenna is the Localizer antenna. The somewhat smaller one below that is the Glideslope antenna. Typically, these types of antennas contain two elements for two ILS systems. Does the A320 have a third ILS system?

Subphase 10th Aug 2015 14:33

Some more pictures.

Source: Jeff Johnson

http://i.imgur.com/ZDPrjrX.jpg

http://i.imgur.com/UA8z7pV.jpg

http://i.imgur.com/TJ0dK8Y.jpg

http://i.imgur.com/34oHYVr.jpg

speedbird_481_papa 10th Aug 2015 17:59

Avionker


They are lightning diverter strips, or that is what I have always known them as anyway. I also suspect that you are correct, and that the radome has been completely punched through and the scanner is visible.
Many thanks for clarifying that!!! I thought they were protector strips but lightning diverters makes more sense :ok:

Regards

Speedbird

gofor 11th Aug 2015 07:41

As asked before by 748Ti, does anyone know what radar was fitted?


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