Syria A320 mid air collision [Archive]

FA10

26th Sep 2012, 13:37

DOVES wrote:

I am going to put them on my file "Superb Airmanship"!

Stilton wrote:

Great job by the crew.

Can you please enlighten me why it is great and/or superb to collide at FL120 in severe CAVOK conditions with a slow moving helicopter?

And special flying skills are not really necessary to bring home an aircraft with half the vertical stabilizer as long as both engines are running.
I guess the pilots were quite amazed by the extension of the damage after they had landed!

BTW - I doubt the fin has been clipped by the rotor blades. The Mil Mi 17 is quite massive, so it would have collided with the Airbus´ wing before sending its rotor blades into the fin. I guess the vertical stabilizer was rather colliding with the fuselage of the chopper.

Juliette Alpha

26th Sep 2012, 13:56

Can you please enlighten me why it is great and/or superb to collide at FL120 in severe CAVOK conditions with a slow moving helicopter?

Apparently the MI-17 was climbing fast to avoid AA fire, if the TCAS wasn't working or the helicopter didn't have a transponder (probable seeing as it is a military aircraft but I don't know anything about that). Flying the aircraft after it has sustained that much damage is good airmanship in most people's books. Although the Airbus systems probably helped a lot, it's still great flying by the crew.

lilflyboy262...2

26th Sep 2012, 14:10

I guess you can say the same about large flocks of birds FA10. They are big and slow moving and they don't show on TCAS either. But no-one has ever crashed into them right?
Do you spend your entire flight with your eyes outside constantly scanning for aircraft? Or is there times, like on decent where your eyes are inside the cockpit briefing and planning for landing?

Oh and of course the rudder is only there for when one engine isn't running... I take it you have lost half your rudder and vertical stab before?

FA10

26th Sep 2012, 14:17

you are absolutely right, there is always a chance to miss something outside. However what strikes me in that discussion is hailing the crew as heroes and comparing them with Sully - when they actually did not have a lot of positive input!

I have tried blocked rudder a couple of times in the sim, half fin is not being offered by the manufacturer...
A fin that is gone completely on an Airbus is not good - ask AA.
Partial supply is obviously enough to fly.

Dg800

26th Sep 2012, 14:49

Apparently the MI-17 was climbing fast to avoid AA fire, if the TCAS wasn't working or the helicopter didn't have a transponder (probable seeing as it is a military aircraft but I don't know anything about that).

I'm pretty sure that even if they do carry one, it's not actually turned on while actively engaging in warfare, as you wouldn't want to draw the enemy's AA fire to you. TCAS was hence most likely out of the question and only see and avoid could have prevented the collision.

DOVES

26th Sep 2012, 14:57

@lomapseo
Well I think that you can file this incident with our data base of how much rudder is needed without asymetrical thrust.
- And dutch & roll without yaw damper and half a rudder?
- And probable hydraulic pressure loss + fluid depletion?
- And landing with some x-wind?
- And compensating for reduced tail weight and down moment?
- And what about stability on vertical axis?
Just some food for thoughts

@FA10
Can you please enlighten me why it is great and/or superb to collide at FL120 in severe CAVOK conditions with a slow moving helicopter?
Who told you who collided with whom?

@waffler
I find it hard to sympathise with a helicopter crew who are killing their own citizens. Some would call it justice.
I completely agree.
"THOU WON'T KILL YOUR BROTHER"

EEngr

26th Sep 2012, 15:18

Anyone know where the rudder hinges and hydraulics are in an A320? It looks like it was cut off high enough to miss these critical parts.

NigelOnDraft

26th Sep 2012, 15:43

I don't see how we can say" great flying" or not... for all we know the crew were almost unaware, or they had a 2.5 HYD sys fail in Mech Backup mode, and recovered after 3 Barrel Rolls :eek:

Why don't we wait and see, and then give praise if due ;)

JW411

26th Sep 2012, 16:16

NoD:

You really are a spoil sport!

Green Guard

26th Sep 2012, 16:16

NigelOnDraft

So ...let's be honest !

You are jealous .... or do not feel comfortable in cockpit.

henra

26th Sep 2012, 18:17

Apparently the MI-17 was climbing fast to avoid AA fire,

Climbing fast in a helicopter at 12kft ? :confused:
What climb rate will be available at a reasonable weight at that altitude?

I feel pretty safe to assume that it will be <<5 m/s.
Climb rate of the Airbus will have been surely significantly higher.
Regarding the speeds I would consider the helicopter almost a stationary 'target'. (350-400kts TAS vs. <100kts). Assuming CAVOK you should be able to see a helicopter the size of a MI-17 at least 5 nm away. That would give you a time window of roughly 45s. In that period the helicopter will have climbed less than 200m. Climbing 5m/s at an approach speed of 200m/s gives you an angle of <1,5°. So if they were flying in a straight line and visibility was OK, climbing of the helicopter shouldn't have been much of a factor.
There must have been other factors involved.
Maybe they were in a turn or blinded by the sun. Otherwise it would be indeed a bit mysterious why they didn't see the helicopter. AoA of the Aircraft itself (3 - 5°) might have been a factor as well.
Will be interesting to see if we ever get an Accident Report on this one!?

Zoyberg

26th Sep 2012, 18:38

Can't have any sympathy for the helicopter crew killing civillians. This is actually a cover story as the Syrian engineers were told to get the aircraft in a hanger to avoid shelling damage ....it wouldn't fit so they cut half the tail off.

keel beam

26th Sep 2012, 19:39

Would an Air France crew have coped?

Golf-Sierra

26th Sep 2012, 21:08

Will Ryanair now clip the rudders on their planes so they can get more pax on whilst keeping their MTOW below the next eurocontrol threshold? The feasibility has been demonstrated.

DozyWannabe

26th Sep 2012, 21:57

Apropos of nothing, would it be remiss of me to point out that the composite lugs remained attached?

autoflight

27th Sep 2012, 07:54

There might be a chance that it was not actually the rotor blade, but simply the fin colliding with the helecopter fusalage. This seems more likely.

Admiral346

27th Sep 2012, 08:26

If my memory serves me right, the rudder on the 320 is driven by all 3 hydraulic systems - so they were very lucky this didn't turn into another siouxcity.

And to who is killing who in this war, especially who is paying for what gun and ammo, the last word has not been spoken in this conflict.
Cui bono?

matkat

27th Sep 2012, 13:06

Admiral, that would not happen as there are hydraulic fuses fitted which sense pressure loss and activate (close) when a pressure drop is detected.

BobnSpike

27th Sep 2012, 13:43

Would an Air France crew have coped?

Of course not, silly. Now, the peanut gallery, on the other hand...

FLR-PSA

27th Sep 2012, 20:33

Something doesn't add up

Primary source of report is state TV
Heli at FL120?
Main rotor strike? Seems unlikely and who saw it?
A320 carries 200 pax?
No eye witness reports

Here's my theory...

MX were pulling the A320 into the hangar, forgot to open the upper door and sliced the stab off. Then, a helicopter was shot down nearby. The rest is journalism.

ravanviman

28th Sep 2012, 02:53

Hmm. You must be an American. Would you be as disparaging if you knew the pilots were American? Give em a break, dude. Bringing a loaded 320-size jet home after any significant mid-air is to be commended. Jeez.

PH-MVK

28th Sep 2012, 06:50

Everybody is assuming they hit each other while flying.
But maybe the helicopter was shot down, and in its path plunging towards the ground it collided with the 320... In other words, they hit the airbus from above. This also could explain why they didn't see them.
(And even if they did see them, it is not that easy to make an abrupt evasive maneuver in a split of a second.)

robdean

28th Sep 2012, 07:23

If the heli was at that FL to avoid AAA/missiles I think it would be most reasonable to assume that it was precautionary rather than a live fire situation. Otherwise one would certainly have to question the wisdom of the routing of the A320... :ugh:

meekmok

28th Sep 2012, 09:05

Reminds me of this:

http://www.talkingproud.us/Military/B52%20No%20Tail/files/b52notail.jpg

Clandestino

28th Sep 2012, 13:05

Would an Air France crew have coped?

Do Syrian pilots regularly practice "Mid-air collision with helicopter resulting in loss of half the vertical stab & rudder" in simulator?

would it be remiss of me to point out that the composite lugs remained attached? Not at all, it is quite an improvement to discussion we are having here.

grizzled

28th Sep 2012, 13:43

1. We have no idea of the geometry of this collision
2. The Syrian MI-17 (regardless of its role) would have been painted in a low-vis camo paint scheme -- the intent of which is to make the aircraft difficult to see against various moving backgrounds.
3. The MI-17 would certainly not have its transponder activated in any mode that would permit (civilian) interrogation and response.
4. Well trained and observant crews in "highly visible" aircraft have had mid-air collisions.

One gets a glimmer of why so many of us who used to be regular contributors to pprune don't post much anymore.

I used to despair. Then I took to simply shaking my head in wonder. Now I just smile.

grizz

lomapaseo

28th Sep 2012, 14:10

One gets a glimmer of why so many of us who used to be regular contributors to pprune don't post much anymore.

I used to despair. Then I took to simply shaking my head in wonder. Now I just smile.

grizz

One gets a glimmer of why so many of us who used to be regular contributors to PPRuNe don't post much anymore.

I used to despair. Then I took to simply shaking my head in wonder. Now I just smile.

grizz

Ah yes, but one or two posts of calibre per thread make it worth while for the rest of us to read :ok:

Lonewolf_50

28th Sep 2012, 15:15

Something doesn't add up

Primary source of report is state TV
Heli at FL120?
Main rotor strike? Seems unlikely and who saw it?
A320 carries 200 pax?
No eye witness reports

FWIW:
Main Rotor is what sticks out furthest from any helicopter, all around the helicopter, with the exception of the tail section and tail rotor on most helicopters. Hence, MOST likely point of contact during a midair. (For tandems like Chinook, you are back to Main Rotor is what sticks out furthest from any helicopter, though the nitpickers will point to refueling probes on some helicopters sticking out a bit further).

Your "seem unlikely" looks to be based on ignorance. (Or, you are having some fun and I didn't catch the tone).

Here's my theory...

MX were pulling the A320 into the hangar, forgot to open the upper door and sliced the stab off. Then, a helicopter was shot down nearby. The rest is journalism.

While amusing ... ??

lomapaseo

28th Sep 2012, 18:32

FWIW:
Main Rotor is what sticks out furthest from any helicopter, all around the helicopter, with the exception of the tail section and tail rotor on most helicopters. Hence, MOST likely point of contact during a midair. (For tandems like Chinook, you are back to Main Rotor is what sticks out furthest from any helicopter, though the nitpickers will point to refueling probes on some helicopters sticking out a bit further).

perhaps a relative sketch of both planes considering their flight path, hovering, climb, path angles, etc. might close some speculation on all sides.

I won't hold my breath that this ever gets into the public domain

cyflyer

28th Sep 2012, 18:40

Otherwise one would certainly have to question the wisdom of the routing of the A320...

As someone has dully noted, if there is a case of AA fire involved, be it cannon fire or the heat seeking variety, what the heck are commercial airliners doing being routed in that same area, or out of Damascus with all that fighting going on ?????? This could have ended very badly for those passengers and crew. The collision could have brought the airliner down, any raving fruitcake with the AA gun could bring the airliner down, and if they have the heat seeking variety, the missile cannot tell between a military helicopter and a civilian airliner. Someone should pay hell for this. All airlines should have suspended flights in and out of Syria until this mess is over with.

broadreach

28th Sep 2012, 20:13

I may have missed it (yes I've looked) but are we sure this flight RB-501 is a daylight operation?

charlie83

29th Sep 2012, 01:44

Admiral, that would not happen as there are hydraulic fuses fitted which sense pressure loss and activate (close) when a pressure drop is detected.

matkat

Don't you mean the hydraulic leak measurement valves?

Anyway, I was of the understanding that they are a manually operated mechanics function via the overhead panel on/off buttons???

Cubs2jets

29th Sep 2012, 10:56

You mean to tell me that there has been a mid-air collision that nearly brought down an airliner and this has NOT been covered by mainstream media and all we have is a SINGLE picture?

I smell a rat.

robdean

29th Sep 2012, 13:01

More photos (http://aviation-safety.net/database/record.php?id=20120920-0)

Lone_Ranger

29th Sep 2012, 17:44

Might not be wise to regard Aviation Herald as a wholly reliable source

parabellum

30th Sep 2012, 03:07

From the pictures I have seen it looks as though the Airbus flew up under the helicopter rotor disk and the main rotor clipped the top of the fin.

Dan Winterland

30th Sep 2012, 03:19

''Quote: Admiral, that would not happen as there are hydraulic fuses fitted which sense pressure loss and activate (close) when a pressure drop is detected.

matkat

Don't you mean the hydraulic leak measurement valves?

Anyway, I was of the understanding that they are a manually operated mechanics function via the overhead panel on/off buttons???''

There are both. The hyd fuses are separate from the leak measurement valves.

Love_joy

30th Sep 2012, 10:03

The most shocking aspect of this event, is that if it happened to an SAA crew at FL120, it could happen to anyone - or me.

The investigation questions are obvious;
What was a heli doing at FL120?
Was either crew cleared to be there?
Controlled, or uncontrolled airspace? Was it see & avoid?
IMC or VMC? (CAVOK by definition does not apply above 5000').

See & avoid in a modern airliner is an uncomfortable position to be in. Closure speeds are too great, and even looking for an other aircraft where you know its position can be difficult.

They were very lucky not to loose both airframes, but I guess sometimes fate is on your side.

lomapaseo

30th Sep 2012, 14:55

From the pictures I have seen it looks as though the Airbus flew up under the helicopter rotor disk and the main rotor clipped the top of the fin

I suspect that it is more likely in that scenario that the Vert Stab hit the copters fuselage and not the rotor.

spargazer

30th Sep 2012, 17:40

Sir, you are a cynic taking a short cut into politics

Morane

30th Sep 2012, 19:42

Pictures look like rotor-blade-impact.
Did a quick search in the net.
Mi17 has a height of 5.65m.
A320 has 11.76m.
Wing passes underneath the helicopter, VS hits the rotor.

Tourist

30th Sep 2012, 20:34

Definate rotor strikes.

Helicopter coming in from the right hand side of the Airbus.
I would (very roughly) guess at the relative speeds giving an approach angle of something like from the A320 pilot's 11 oclock, and anything from the 2 o'clock to the 4 o'clock for the Mi8 pilot.

First blade (rotating clockwise seen from above) strikes the lower shallower cut, then second blade comes in deeper and shears off the top of the A320 tail.

Alternatively, the A320 was parked, and the Mi8 hover-taxied into the back of it from the 7 o'clock.......

glad rag

30th Sep 2012, 21:36

http://aviation-safety.net/photos/accidents/750/20120920-0-C-d-2-750.jpg

Hmm second partial rotor strike there??

parabellum

1st Oct 2012, 00:46

I suspect that it is more likely in that scenario that the Vert Stab hit the
copters fuselage and not the rotor.

lomapaseo: I think the damage to the fin shows unmistakable blade damage, don't you?:confused:

Lonewolf_50

1st Oct 2012, 19:40

Alternatively, the A320 was parked, and the Mi8 hover-taxied into the back of it from the 7 o'clock

Could be. But, it appears that the damage happened in the air ...

ASN Aircraft accident Airbus A320-232 YK-AKF Duma (http://aviation-safety.net/database/record.php?id=20120920-0)

Looks like a rotor strike on that vert fin of the Airbus.

With that damage, nice job getting her down. :D

hedgehopper

1st Oct 2012, 20:38

Anybody have photos of the rotary remains?

no report in the media of a helo. crash...

WanganuiLad

1st Oct 2012, 20:50

It's a war zone, good luck finding shots of the helicopter unless they are uploaded by the 'rebels'

Christodoulidesd

2nd Oct 2012, 12:18

@lone_ranger: what's wrong with avherald? Are you serious ?

TBSC

2nd Oct 2012, 14:26

Other than it's full of incorrect information and guesses from news reports?

Lonewolf_50

2nd Oct 2012, 15:46

hedgehopper, I seem to recall that there was a media report about this a week or so back, which led with the helicopter going down.

ZeBedie

2nd Oct 2012, 16:16

Passenger 389

2nd Oct 2012, 16:59

hedgehopper, I seem to recall that there was a media report about this a week or so back, which led with the helicopter going down.

Lonewolf_50 is correct. The following is from an article that was published on the Voice of America website on September 20, 2012:

"Syrian state television says a military helicopter that crashed near Damascus clipped the tail of a Syrian passenger plane in midair. The report said the passenger jet landed safely Thursday at Damascus International Airport with 200 people onboard."

"Opposition activists said rebels shot down the helicopter. Fighters opposed to Syrian President Bashar al-Assad have claimed to have downed military helicopters before, including late last month in Damascus."

"The Syrian state report did not include eye witnesses to the alleged incident."

sandos

3rd Oct 2012, 20:23

The lower slice in the rudder/fin was obviously done from behind. I guess that's plausible, since rotor tip speed would be higher than the 350kts TAS of the A320. But on the other hand, wouldn't the rotor have lost the majority of it's energy with the first strike - the one that went right through?

I think you slightly underestimate the power in the main rotor: https://www.youtube.com/watch?v=vm398hEzH8E

Notice how the rotation does not stop even when impacting the ground. I only fly RC helos, albeit with totally different weight ratios but I do have respect for flying blenders of every size above ~60 cm. Also, does it really take that much energy to cut through a light-weight aircraft structure? Its not exactly steel/concrete.

Roger Greendeck

3rd Oct 2012, 22:48

Main rotor energy is substantial and it wont stop on first impact when it hits anything. If the object s robust enought the blade/hub assembly may shatter or depart the head BT the following blades will keep coming at pretty much the same speed. Whilst I can't comment on the veracity of this particular story the impact marks on the tail are consistent with a mid air strike I have seen.

HAWK21M

4th Oct 2012, 09:18

What does TCAS say on both Aircraft......

Lonewolf_50

4th Oct 2012, 12:41

Hawk, why do you assume that there is TCAS in a helicopter?

BobnSpike

4th Oct 2012, 13:06

...or that it would be on in an active anti-air environment

Herod

4th Oct 2012, 16:46

If the heli was shot down by the rebels, what sort of missile homing system would they have? Seems to me that having heat-seeking missiles fired off anywhere near an airliner is a bad idea.

rcsa

4th Oct 2012, 17:43

We believe the helo was not shot down by rebels. It was avoiding being shot down when it collided with the A320.

Which ultimately had the same effect as being shot down.

The FSA and other rebel units may have MANPAD heat-seeking AA systems, but most of the reporting has had them firing AAA (mostly 20mm) in the general direction of ASA aircraft. Any hits have been more by luck than judgement.

Others have noted there would likely be no TCAS in a military helicopter flying a combat mission.

Even if the A320 crew knew they were in danger of a collision, they would have had little or no idea what they were trying to avoid, where it was coming from, how fast it was going, or how to avoid it.

Good luck + good airmanship + some more good luck.

Tourist

7th Oct 2012, 15:18

"Is it not supposed to be a forum for pilots?"

"but I guess it may have begun a fast descent"

Hmm.

1. Exactly how fast do you think a helicopter such as a Hip can descend?

2. Exactly how high above terrain do you think this sort of move generally begins?

Lonewolf_50

10th Oct 2012, 13:56

Helicopter autorotative descent: would need to take a peak at the Hip's flight manual, but I'd guess 3-5000 FPM is in the ball park. ;)

As to "height above terrain" this story makes me scratch my head a bit. Helicopter up at 12K is an altitude that must have been chosen for a purpose. With Damascus roughly 2200 feet above MSL, that's still about 10K AGL ... which leads me to guess that this flight profile was chosen to avoid small arms fire. (I may be wrong.)

But it got hit anyway? Seems to me that some actual AAA like a 57mm might be involved if that were the case.

Ran into another plane because neither cockpit crew saw one another? Most likely explanation from where I sit.

A lot I don't "get" about this one.

Tourist

11th Oct 2012, 08:28

Lonewolf

No, as with just about all helicopters, 2500-3000ftpm is more realistic, to descend faster you would either need high angle of bank, or a temporary dive, and neither would give a straight cut.

High speed descents are a small arms fire procedure, so usually start approx 2000ft agl as that is the threat zone. There is no point whatsoever in starting the dirty dive at 10000ft agl. The dive can only go on for a little while in a helicopter before vmax at which point you are stabilised at a low rate of descent again.

I speak as one of the few( only ) people on here to fly both types of aircraft involved.

wild goose

11th Oct 2012, 22:59

What if the A320 had been on the ground and the Hip struck it whilst maneuvering too close - say - at night or otherwise?
The Syrian propaganda machine can't be trusted for the decent truth - anything threatening their public can be expected to be altered in the news.

The Hip wouldn't have TCAS but it has a transponder (IFF).
Regarding an earlier post here - the rebels dont have aircraft
If they tried to operate them, they would be blasted out of the sky in an instant.
Also, the rebels dont have SSR to pick up a transponder/IFF. At best they may have 57mm but in all likelihood its light AAA like 23mm or 14.5mm.

Lonewolf_50

15th Oct 2012, 14:16

Tourist: your response was only in part to what I commented upon. The rest you seem to be thinking out loud.
No, as with just about all helicopters, 2500-3000ftpm is more realistic, to descend faster you would either need high angle of bank, or a temporary dive, and neither would give a straight cut.
"Just about all helicopters?"
Not going down that rat hole, but I'll accept I may have been a bit high on the ball park. As I've not flown any Mi I'll take your word for it.

How fast you descend depends on how fast you want to fall, if you fly max glide or max range auto, if you slip, gross weight of the helo, density altitude ... but you know most of that.
High speed descents are a small arms fire procedure, so usually start approx 2000ft agl as that is the threat zone. There is no point whatsoever in starting the dirty dive at 10000ft agl.
Agreed, from my own experience, apart from the fact that I never suggested a "dive" dirty or otherwise.

What I was talking about was that he may have been flying that high to AVOID small arms fire.
The dive can only go on for a little while in a helicopter before vmax at which point you are stabilised at a low rate of descent again.
Dive? Anyone who has flown military helicopters knows the limitations of the airframe in regards to missile avoidance maneuvers. And small arms fire avoidance maneuvers. You seem to be using "dive" where I did not.

Are we even having the same conversation?

There is a max airspeed that you limit yourself to in order to avoid retreating blade stall, if you know your aircraft. That does not preclude a high speed descent, nor an autorotative descent. FWIW, I'd suggest you

1. Try not to teach your grandmother to suck eggs, and
2. remember that I know how to fly helicopters.
3. See above comment on why the helicopter may have been up that high.

I speak as one of the few( only ) people on here to fly both types of aircraft involved.
Cheers.

Had you understood my point about high altitude to avoid small arms fire, you'd most likely not have responded as you did.

Tourist

17th Oct 2012, 22:11

Not teaching you to suck eggs lonewolf, but small arms threat zone is 2000ft. 10000 and up is certainly not "small arms"
territory.

Lonewolf_50

18th Oct 2012, 15:20

I see that you have missed the point yet again.
Not wasting further time.

Take care, fly safe.

Abu Ali

2nd Mar 2013, 21:40

JammedStab

3rd Mar 2013, 10:15

Hello all,

I was on this flight and indeed know that we were very lucky.

I'm reading all your comments with great interest because I'm trying to understand the technical side of the incident, as a non-technical person.

I'd like to combine my first-hand experience with your technical knowledge in order to have a more complete picture, and would be open to answer any questions.

Thank you,

Just tell us what your experience was. From where you were sitting, what you felt, saw and heard. Time of day. How the aircraft flew after the collision. The reaction of the flight crew and flight attendants. Preparation for emergency landing etc.