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A321 heavy hail damage in Seoul - landed without radar..?

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A321 heavy hail damage in Seoul - landed without radar..?

Old 10th Jun 2006, 17:33
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A321 heavy hail damage in Seoul - landed without radar..?

Hi all,

Norwegian newspaper VG reports today that a A321 landed safely in Seoul after recieving heavy hail damage. (URL with picture: http://www.vg.no/pub/vgart.hbs?artid=119240).

VG makes a scene about the amazing job of landing the bus without radar. Now, why would a radar be essential to flight? I take it it's the WX radar that has been knocked out, given the picture and what they write. I haven't found any international news, so I'll translate into English:
--------------------------
"Had to land blind

(VG Nett) A storm of hail gave the pilots a big challenge: they had to land with a destroyed aircraft nose, without radar, and without being able to look out the windows. On board was 200 passengers.

Extreme landing: The pilots made the impossible and landed the aircraft with 200 passengeres, without the use of radar and without looking out the windows.. Photo: Reuters



Asiana Airlines flight 8942 flew straight into a strom of hail enroute from Cheju to Seoul.

Hail tormented the aircraft, and when it finally did escape the strom, it had recieved heavy damage.

- Hail tore off the aircrafts nose and smashed the pilots' windows, said an spokesperson for the Airline to Reuters.

The hail knocked out the main circuit to the radar system and punched holes in the protetction shield around the engines.

That gave the pilots a big challenge. Because even though the windows in the aircraft type A321 was made of safety glass, and remained in their place even after the hits, it was almost impossible to look through them.

177 school children on boad.

- Our pilots had to land manually without being able to look forward, said the spokesperson.

Only the small side windows in the cokcpit were whole, and were the only possiblity the pilots had to look outside, where to land.

There were 200 passengers on board.. 177 of the were school children that had been on a field trip.

Recieving award

Incredibly enough, the pilots managed to get everyone safely down. Without any form of outside view and no radar, the airplane landed on the runway in Seoul.

No one was injured, and captain Lee Chang-ho and first officer Kim Yong-ik may now expect proofs of honor for their engagement.

Hail is, according to the company's spokesperson, a huge risk to aircraft travelling at high speeds."
---------------------------------

Now, I do of course see the tremendous seriousity of this incident, but I'm merely wondering if I've completely lost my sense of aircraft systems, or if it's VG that is messing up. Now, why are they going on about the radar? Do they mean the avionics suite, or simply the WX radar?

Now, if the main systems in the cockpit were not destroyed, I guess I would be right to say that the cockpit crew did indeed have other indications as to their position than the small side windows? I do not know the bus' systems intimately, but i guess both (dual?) ILS recievers as well as GPS and IRS/INS would be able to give some vital clues.

Am I mistaken, or is the WX radar about as important to the landing phase as a box of cookies?


Cheers,
bfisk
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Old 10th Jun 2006, 19:04
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Given no NAV data, one can tilt the radar antenna down to look for large features such as coastlines and such. Other than that, radar is as you suggest only used for things like shear detection and storm avoidance - the weather.

The article focus should have been on the lack visibility through the L1 and R1 panes as this is where the true challenge existed. Perhaps they elected to do an autoland - not sure what category ILS RKSI or RKSS has.

With no approved autoland available, I think a good landing is bordering on heroic using the side windows only in an aircraft this size - (taildragger memories anyone ?) - and of course traffic avoidance would also be impossible without TCAS equipment and terminal radar in this condition.

Good job ! Those school kids now have a great story to tell.
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Old 10th Jun 2006, 20:27
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Originally Posted by bfisk
Hi all,
Norwegian newspaper VG reports today that a A321 landed safely in Seoul after recieving heavy hail damage. (URL with picture: http://www.vg.no/pub/vgart.hbs?artid=119240).
VG makes a scene about the amazing job of landing the bus without radar. Now, why would a radar be essential to flight? I take it it's the WX radar that has been knocked out, given the picture and what they write.
Am I mistaken, or is the WX radar about as important to the landing phase as a box of cookies?
Cheers,
bfisk
One would get the sense that the weather radar wasn't working well before either, otherwise how would they have flown into a hailstorm of that magnitude. They may be looking for awards for a heroic landing, but they might also be looking into an inquiry as to how they put themselves in that position in the first place.
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Old 11th Jun 2006, 00:17
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Regardless, hats off to the crew for suffering this damage and getting down safely, it must have been quite an event.
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Old 11th Jun 2006, 01:53
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One would get the sense that the weather radar wasn't working well before either, otherwise how would they have flown into a hailstorm of that magnitude.
1.Weather radars have a hard time seeing hail - if it is 'dry'.
2.All types of hail may be carried many miles from fathering storm clouds.

This is how it can appear with no apparent warning - catching crews by surprise - in this case an unpleasant one.
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Old 11th Jun 2006, 02:03
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No matter what they did or did not have, a good job done in getting the bus down in one piece.
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Old 11th Jun 2006, 02:14
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Thumbs down gulity as negligence of duty

Korean Newspaper told that "According to aviation specialist....fortunately It is just a Wx radar not navigation system....."

Let me tell you something.

Last year asiana had same incident over china.
That time they had problem on one of the Wx radar systems. but the maintenance put placard on the other good wx radar system. Pilot flied on broken radar and met the hail.
Captain lost his forward window vision due to cracked window and let F/O flied A/C and landed safely on chang choon, china.

then What are you expecting?

Captain lost his stripe and company blamed him as an negligence of duty and degraded him as a F/O and he is flying on disgrace as a F/O.

Yesterday, There was no problem on Wx radar. He got through TS. I wonder why. He was the only one A/C heading into TS among the several A/C on same area.

Don't get me wrong. I'm not blaming him for that. On the contrary He did good job after incident. He managed rest of flight and landed safely. There might be some unknown situation which he coundn't avoid TS. He did good job after all.

But this time, company awarded him and consider to give priority on promotion. Bear in mind asiana doesn't have SENIORITY system. Damn management scabs took everything.

Yeah, Here is what I want to say. SCABS.

The only difference between two captains.
First one was union member, later one was scabs who was begging his captain position to management and betrayed his fellows on last strike.

NOW he has awared well-done while union captain is still flying as a F/O.

What the F*** is this!

Expat doesn't make much difference in asiana.
If you mess up with scab pilots or management. you are dead meat.
Scabs has their own line with management. they will report you to management not because of your flying skill but because of your attitude to scabs.

Be careful.

What a unfair world we live!


P.S. according to the airport worker's, nose cone was attached until he landed and he lost nose cone during taxi. tricky pavement taxiway, huh?
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Old 11th Jun 2006, 04:01
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Originally Posted by vapilot2004
1.Weather radars have a hard time seeing hail - if it is 'dry'.
2.All types of hail may be carried many miles from fathering storm clouds.

This is how it can appear with no apparent warning - catching crews by surprise - in this case an unpleasant one.
I don't agree. It's all about how you use the tilt control on the wx radar. A common mistake is to not tilt the radar low enough to "see" into the cell at the level where all the water is which is the best reflector of the radar beam ie you won't get a "paint" if the beam isn't targeted correctly. Once it's established where the cell is then it's a matter of avoiding it with enough distance to minimise any problem with turbulence, hail etc.
No doubt the crew did a great job in getting the aircraft on the ground but I question their use of the wx radar in the first instance.
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Old 11th Jun 2006, 06:04
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I agree with you, preset.

If it was really that difficult for Wx radar to detect the type of hail-generating systems described in this article, then such things would be commonplace.

Wasn't another hail-damaged aircraft (a year or so ago) the result of that company's SOP which allowed the crews to fly with Wx radar off if there were no Cbs forecast along the route....

Congrats on the landing, of course - but questions at the cause.
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Old 11th Jun 2006, 07:04
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I heard this story reported on BBC Radio Five Live yesterday morning on their 11.00 bulletin.

They reported that the crew were being praised (hailed?) as heros, landing the a/c after the windscreen had been shattered and the radar and propeller had been knocked out.

Looked at the photo again. True - no sign of a propeller
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Old 11th Jun 2006, 07:15
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Good Job? Hats Off? Heroes?

Tail wagging the dog here I'm afraid.

To get an aircraft into that state you have to do silly things - like
flying with the radar off in the first place - ignoring echoes - ignoring
all the warnings you had in training about the foolhardiness of entering
a CB cell.

Then, once the ship is damaged - and by the way there are other antennae in the nose cone too - depending on aircraft type, the ILS GP antenna for
instance - you have to get it down and are a hero...

Over the years this has happenned to my knowledge to a Spanish DC-9 over Valencia - landed in Barcelona with hugely dented slats, radome off, opaque windows - all radio antennae gone and one engine out... also a Korean 747 over the Alps, which landed in a non surprisingly similar state in Zürich. (That one then, following minimum repairs by a Boeing team, later took off on a ferry flight without applying the Boeing recommended TO corrections and staggered off the runway end and over the church tower in Kloten).

Both these ships had flown into CB cells - the Spanish DC-9 knowingly ("It only looked like a small cell...") and the Korean with the radar off.

Thunderstorm cells can have hail as big as dinner plates. Apart from that they are full of supercooled water ready to ice you up and severe turbulence. Stay out of them and be a quiet hero!

FC.
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Old 11th Jun 2006, 07:59
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From an AAIB report after an A321 was badly damaged by hail in 2003
(http://www.aaib.gov.uk/sites/aaib/cm...pdf_029049.pdf):

"The radar was set to a scale of 160 nm and with no significant returns ahead and no thunderstorm activity forecast the radar was switched OFF. The aircraft had been in clear skies above towering Cu for most of the flight and, in accordance with normal procedures, the radar had only been turned on when required."

""Recorded data concerning the use of the weather radar showed that it was switched on and displayed to the first officer for approximately 12 minutes as the aircraft climbed from 4,700 feet through 23,600 feet. The DFDR did not record any use of the weather radar during the remainder of the flight."

The following recommendations were made:

"Recommendation

Present guidance material not only suggests that, in areas of thunderstorm activity, readjusting the radar tilt frequently is the only way to monitor storm development but also that when the upper limit of the storm cell is determined it should be avoided vertically by at least 5,000 feet. The inability of weather radar to detect certain types of precipitation, associated with storm cells, in the upper levels of the atmosphere above 30,000 feet however make it impossible to determine with any accuracy the upper limit of a cell when its vertical development exceeds 30,000 feet. Calculations to determine the aircraft's clearance above the upper limit of a cell can therefore be inaccurate resulting in an aircraft entering the active element of a storm cell whilst attempting to safety over-fly it.

It is therefore recommended that:

Safety Recommendation 2004-47

The Civil Aviation Authority should consider reviewing their guidance material concerning the use and interpretation of airborne weather radar, with a view to highlighting the potential for displayed data to be unreliable when used for calculating the safe vertical clearance for overflight of active storm cells.
"

The CAA later accepted this recommendation:

"CAA Response

The CAA accepts this Recommendation.

The CAA has reviewed the guidance material contained in Aeronautical Information Circular (AIC) 72/2001 entitled ‘The Effect of Thunderstorms and Associated Turbulence on Aircraft Operations’ and has amended and updated it as necessary. In particular it covers the subject of the use and interpretation of airborne weather radar with regard to calculating the safe vertical clearance for the overflight of active storm cells. This includes highlighting the potential for the displayed data of the weather radar to be unreliable when used for these calculations."


The revised AIC was later published as AIC 81/2004 (Pink 66) on 19 August 2004. It can be viewed at http://www.ais.org.uk/aes/pubs/aip/pdf/aic/4P066.PDF if you are registered with UK AIS.
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Old 11th Jun 2006, 08:09
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SCMP Hong Kong

South China Morning Post reports today:

The nose of the plane, which contains the radar, was completely blown off and technicians later discovered a 1cm hole in the exterior of the engine.

The freak hailstorm destroyed the plane's autopilot and severely damaged the cockpit's forward windows, leaving only the side windows intact for the pilots to see the runway.........brought the plane safely to the ground manually at 6pm, only 15 minutes later than scheduled

"The radar showed no clouds and I thought we had passed the clouds. But suddenly it hailed and rained" Captain Lee said


Hardest bit seems the manual landing with frosted window visibility
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Old 12th Jun 2006, 07:21
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old trick

One old trick (in cruise) is to put the scale to 80nm., tilt the radar until ground echoes are visible at 40nm. and then any echo inside the 40 mile range is a CB. After that you can alter tilt and range as needed to deal with the CB so found.

This works in mountainous areas too, though there you need to get ground echoes to 30nm.

FC.
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Old 12th Jun 2006, 07:29
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New Trick

Even better,the auto-tilt on some of the new busses works great
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Old 12th Jun 2006, 11:28
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Few cloudy, thanks for the tip; operation of the wx radar seems to still carry quite some mystique around it.

sec-3, anything which includes the word "auto" needs monitoring, so you might as well do it yourself if you actually know how to.

manincrz2937: thx for the background story!
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Old 12th Jun 2006, 12:31
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Well, once more, how about the maxim: A superior pilot is one who uses his superior judgement to avoid those situations that might require his superior skills

Some tips, in addition to the ones provided by "Few Cloudy":
- Use the different tilt and range available through the right (or left) ND or any additional display to top your own
- Observe the shape of the reflections
- Colors do not mean color, e.g. green is ok at 3'000 but an absolute no fly thru at 30K+
- Look outside of the window
- Switch the radar early enough, which means before entering clouds
- All clouds are suspect
- Do not take off with defective radar equipment
- As a general rule, cells move with the prevalent wind. But some also do move against the wind!

Any more?
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Old 12th Jun 2006, 12:39
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Although all my Wx avoidance was based on 50 year old 'cloud and clonk' orange porridge technology, I would add:

Avoid areas where rates of change of intensity are highest.
ALWAYS fly with the Wx radar on!
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Old 12th Jun 2006, 12:39
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In the company I work for, the WX radar is swtiched on on line up and isn't switched off till after vacating the runway.......

MEL is very restrictive on departing without WX radar.....
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Old 12th Jun 2006, 13:09
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And at high cruise altitudes (27,000 to 37000?) the manufacturer's hand book for Collins WXR-700X radar recommends adjusting the gain control to full max gain for scanning ahead. This gives a much more powerful radar beam to that in auto. Low reflectivity targets such as Cb tops which consist of ice crystals may not show up in auto but in max gain will then be displayed as a tiny return - enough to warn you of a Cb top ahead. Then switch back to auto gain to evaluate the solid storm cloud below that is causing the Cb top. Repeat as required. Have used this technique over the Pacific regions for years and it certainly works, much to my relief at night.
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