Ryanair B738 near Zurich on Feb 6th 2012, loss of cabin pressure

[I-2021]

A Ryanair Boeing 737-800, registration EI-DCK performing flight FR-4523 from Milan Bergamo (Italy) to Brussels Charleroi (Belgium), was climbing through FL360 out of Bergamo about 40nm southeast of Zurich (Switzerland) when the crew donned their oxygen masks and initiated an emergency descent to FL100 (average sinkrate about 4300 feet/min) reporting a rapid decompression of their aircraft. The aircraft continued on FL100, later FL080 to destination for a safe landing on Charleroi's runway 25 about one hour after initiating the emergency descent.

Source : Avherald.com

1 hour unpressurized looks quite interesting. Safest/best course of actions ?

[JW411]

Well, once you are down at F100 and assuming that you don't have a terrain problem, then what is the problem with continuing to destination as long as you have enough fuel to do it?

[Nubboy]

Assertain state of passengers and crew. Resolve why the pressurisation failed, make a decision. Simples, peoples.

[golfyankeesierra]

If you have a decompression mid-atlantic at 30W, an airport is a lot longer away then 1 hour..

[Monstermunch]

Well done to the crew!:ok:

[Artie Fufkin]

The only thing news worthy is that RYR tanker around sufficient extra fuel to allow them to get to Brussels approx 30,000 ft lower than flight plan!

Isn't there a lot of cumulus granite "40 miles south east of Zurich"?

[Telstar]

1 hour unpressurized looks quite interesting. Safest/best course of actions ?

If the facts are as reported and they usually aren't: by the time the descent is actioned, by the time you have run the checks, communicated with the cabin crew, made PAs to reassure passengers(more then likely in more then one language) and established a plan of action, communicated with the company and allowed extra mileage for a descent rate of 500fpm for the remainder of the flight you will be as near as makes no difference to CRL. May as well continue to destination if no one requires emergency treatment.

I'm sure this thread will descend into total hysterics by uneducated and uninformed muppets because Ryanair has been mentioned. Ho Hum.

[Basil]

Subject, of course, to terrain:
It is common to ski at 12,000ft or more so sitting down at 10,000ft shouldn't be a problem.
Don't forget that the cabin altitude in the cruise will be 6,000 - 8,000ft.
Looks like a good decision.

[DOVES]

Quote:
"Well, once you are down at F100...
:{... and assuming that you don't have a terrain problem,...:{
then what is the problem with continuing to destination as long as you have enough fuel to do it?

Quote:
Isn't there a lot of cumulus granite "40 miles south east of Zurich"?

It's a long time since my last flight over the Alps, but I seem to recall that between Saronno and Trasandingen the MEA should be 14000 feet. And, during the emergency descent is wise to turn left or right to avoid traffic, and on both sides, the minima and granite don't fall.

[racedo]

Ryanair pilots do job safely shocker.:ugh:

[fireflybob]

It's a long time since my last flight over the Alps, but I seem to recall that between Saronno and Trasandingen the MEA should be 14000 feet. And, during the emergency descent is wise to turn left or right to avoid traffic, and on both sides, the minima and granite don't fall.

Ever heard of ATC that have a facility called radar who can assist you in which way to fly and ensure you're at a safe altitude for the area?

[DOVES]

"Ever heard of ATC that have a facility called radar who can assist you in which way to fly and ensure you're at a safe altitude for the area?"
I reply:
"Do You know how long it takes to get down to 14.000' from F360 during an Emergency Descent?"
"And You suppose that the PNF (or Pilot Monitoring, how You call him now) has enough time to do anything more than Don Mask, Establish Communication, Declare MAY DAY, Check Air Conditioning & Pressurization: Like: -Zurich Radar this is Ryan air 4523. I am requesting radar vectors and altitude to descend to, to avoid mountains-???????

[fireflybob]

"Do You know how long it takes to get down to 14.000' from F360 during an Emergency Descent?"
"And You suppose that the PNF (or Pilot Monitoring, how You call him now) has enough time to do anything more than Don Mask, Establish Communication, Declare MAY DAY, Check Air Conditioning & Pressurization: Like: -Zurich Radar this is Ryan air 4523. I am requesting radar vectors and altitude to descend to, to avoid mountains-???????

As someone who has been in the business circa 40 years, yes I do!

In a radar environment any controller worth his salt (and the Swiss are certainly one of the best) would certainly come up with a heading and information on safety altitude. That doesn't mean you can assume such assistance is there (many airlines have escape routes to cover such a contingency). It wouldnt take more than a few seconds for ATC to provide this information!

[Callsign Kilo]

Cabin Alt Warning (B737NG)

FO - Dons O2 mask verifies regulator @ 100%
Establishes comms with PF (Capt)
Cancels cabin alt warning horn (hopefully)
Sets Pressurisation Mode Selector to manual
Closes outflow valve
If cabin altitude is approaching or exceeding 14000' advises PF

Emergency Descent

FO- Pax signs on
Pax O2 verified on / guard opened and switch on
Engines start switch to CON
Sets 7700 in TXR and selects TA Only
Calls ATC - Mayday, Emergency descent, current heading requesting MSA
regional pressure setting
Reads related checklists
Monitors for descent into icing conditions
Calls passing each 10,000'
Calls two to go and one to go to level off
Monitors Captains actions and calls out omissions

A :mad: load. All to be done in this order by memory.

[fireflybob]

A :mad: load. All to be done in this order by memory.

Callsign Kilo, agree but isn't that why we practice in the simulator?

[Callsign Kilo]

Indeed, and it isn't practiced enough in my opinion. Probably because it is a time consuming exercise! The problem here is that crews become unfamiliar with the memory items and omitt many when put to the test. In my opinion we are all very good at the 'engine fire or severe damage or seperation' stuff (repeated every 6 months) but crap with most others. History suggests that pressurisation issues are more likely than engine malfunction on the 737. The pressurisation system is it's weakness

[pmizrahi]

Enroute from Le Bourget to Linate, I heard ATC clear this Ryanair flight down to FL100. They also advised the crew of a 7.000 feet MSA and provided a regional QNH.

[DOVES]

And as far as I remember:
The radar controller is only responsible for obstacle clearance after having pronounced: "This will be a radar vectoring for a final ILS (or what else) approach for runway ..."

With almost 5000'/min rate it takes a little more than 4 minutes to get down from F360 to 14000'; it's not such a long time to... "Aviate, navigate, communicate" & "Dive and drive"!!!

[PENKO]

What is the issue? Any pilot worth his license knows the MSA/MEA/MORA of the route he is flying. It is an item on any emergency descent checklist: descend to MSA/FL100.

So, the Ryanair had enough fuel to continue to destination. Well done.

[Pennellino]

just checked on flightradar and have noticed that on northern Alps boundary they reached very soon FL100...then plenty of enroute alternates, many of them suitable, passed by to go straight on final for ILS at CRL.
Perhaps something better could have been done. Anyway a successful emergency manoeuvre, done with very high probability in a professional way.

[2EggOmelette]

Certain I briefly saw the thread yesterday after it was moved. Had been attached to another Ryanair one. Cant remember the title, or under what forum (something to do with specific airlines/bases?), just that it was up to about 2000 comments. Not sure what was going on there:eek:

[wayupthere]

I thought MOL believed in all publicity is good publicity?!

[captplaystation]

And what about the "alleged" incident in BCN where an AA aircraft had its stab touched by a RYR winglet at the holding point, Capt was "allegedly"notified via an Engineer sitting at the overwing who alerted the CC, but nonetheless said nothing to the Tower ,or the AA aircraft, flew 2 sectors & then p1ssed off home without writing anything in the tech-log, but having had a quick look at the wing before leaving ( as this is 3rd hand, I will add again "allegedly" )

"Allegedly" the AA had a fair bit of damage on arrival, having traversed the Atlantic.
If true, strange how the person concerned, with (allegedly) one previous off runway misdemeanour to her name, has suffered only a seat change. (must give REALLY good head :D)

[Mabbs9]

Just spoke to my cousin who was a pax on the this flight. It ws en route stansted. She said the masks dropped when over the Alps and the Flt Crew over the PA said " mayday emergency landing"! She was petrified and assumed a crash landing in the mountains.

She smelt burning but thinking back, the 73 has chemical oxy generators for pax ox. They did an emergency descent and diverted to FRA. She was extremely relieved to hear they weren't crash landing! Shame about the misleading announcement.

The Ox masks can be a bit of a pain (flight crew), poss inadvertent transmission on the PA. Defo not a time that I'd be considering talking to the pax!

Al'ls well that ends well and she's not too worried about her return flt on wed now.

[Mabbs9]

Hmm, not convinced this is the same Ryan flight. I though hers was more recently but failed to ask. It was Bergamo Standsted so very likely the same flight with some eroors in previous reports. She also said the newspaper write ups, no surprise here, were total crap.

[supersani]

Mabbs

Your incident is covered here (http://www.pprune.org/spectators-balcony-spotters-corner/481883-three-examined-hospital-after-ryanair-emergency-descent.html)

[Discorde]

With almost 5000'/min rate it takes a little more than 4 minutes to get down from F360 to 14000'; it's not such a long time to... "Aviate, navigate, communicate" & "Dive and drive"!!!

How expeditious does the descent need to be after loss of cabin pressure? There will be at least 10 minutes' worth of oxygen for pax and crew (and probably more for the pilots). A quote from 'How To Do Well In The Sim': (http://steemrok.com/howtodowellv3)

<<When you call 'MAYDAY', if you can get some sort of ATC clearance before you plummet, so much the better. It would be pointless doing the drill perfectly and then slamming into another aircraft beneath you on the way down. The TCAS telling you 'CLIMB . . . CLIMB' won’t be much use at this point. The question is: 'how long do I spend trying to get an emergency descent clearance?' And of course no-one can give you an answer – you must use your judgement as to when to start down if ATC can’t help. However, remember you've got 12 minutes of passenger and cabin crew oxygen available and considerably more for the pilots. If you stay aloft a short time while you get a clearance and then descend at current IAS (in case of damage) you'll still have plenty of time to get down to breathable air before the oxygen runs out.

One of the difficulties in this scenario is communication with cabin crew – they can't talk to you with their masks on, so it's one way traffic only. Having done the QRH checklist you could do a combined PA for both the cabin crew and the pax, along the lines of: '. . . we've lost cabin pressure, so everyone make sure you've got your oxygen masks on . . . cabin crew stand by for further instructions . . .'. At the end of the descent your PA could be '. . . cabin manager, take off your mask and report to the flight deck . . .' Or if for some reason you need to talk to the cabin manager during the descent, you could tell him on the PA to don a portable bottle and report to the flight deck. He can then listen to what you say over the speaker.>>

The 12 minutes refers to the B757/767 but I would expect other aircraft to have similar oxygen endurance.

[A37575]

The pressurisation system is it's weakness

Really? I flew the 737 series for 12 years and had only one pressurisation problem. It turned out to be finger trouble on my part. I think it is drawing a long bow to claim the pressurisation system is the 737 weakness.

[Meikleour]

Discorde: Above 30,000ft. cabin altitude the human body needs pressurised O2 to function correctly. This is supplied to the pilots through their equipment but is not afforded to the passengers who only have free-flow O2. Therefore I would suggest that extended periods at very high cabin altitudes (ie. 30,000+ ) is not a good idea. I am sure that certification requirements assume a response time scale.

[Discorde]

Good point, Meikleour. It's a judgement call, or risk analysis if you like. There are competing demands - the need to restore normal breathing capability and the need to avoid other traffic during the descent. Additionally, a violent decompression might signify aircraft damage, which requires restricting IAS, and hence reducing descent rate.

Above 30,000 feet, if you descend at current IAS (with speedbrake deployed) you'll initially maintain a highish Mach No & descent rate. Both of these parameters will reduce as altitude reduces. But by then atmospheric oxygen partial pressure is increasing. This procedure will bring you down to breathable air reasonably quickly.

[Meikleour]

Hi Discorde: I was not trying to open a debate about damage/no damage descent techniques I was merely trying to draw attention to an area that in my experience is scantily covered during training. Namely the risk to passenger health at excessive cabin altitudes. Once below 30,000ft. the risk is vastly reduced. I am sure that you will remember that a certain three- engined product from Hatfield did not even have a pax dropdown system fitted! Cue here to review response time!

This factor is more common now with so many aircraft operating at F390/F410 today.

[Discorde]

De Havilland's tri-motor was always more enthusiastic about descending than climbing, particularly with reverse pulled on 1 & 3. So no need for drop-down oxygen!

[FCeng84]

The FARs call out two basic requirements for maximum cabin altitude:

1. Never above 40K feet.

2. Time above 25K feet shall be less than 2 minutes.

The first one is usually met by assuming a "reasonable hole size" - about the size of a single cabin window. With airplane ceilings at about 43K feet, it does not take much of a descent to satisfy #1.

The second requirement above is the tricky one. The airplane must essentially be able to descend to 25K feet true altitude in two minutes or less. The proceedure is speedbrakes up, idle thrust, push over to accelerate to near Mmo. Transitioning from Mmo to Vmo is a bit of a challenge as it requires pulling the nose up several degrees. Descent along a line of constant Mach number involves accelerating in terms of true airspeed. Descent along a line of constant Vcas involves decelerating in terms of true airspeed. Fortunately the Vmo/Mmo corner altitude is not much above 25K feet for most models so once you are down to the point where you reach Vmo you are almost down to 25K.

Another consideration is that while emergency descent rate is slowest when heavily loaded, a heavy airplane will be cruising at a slightly lower altitude than a lighter one and thus does not have as far to go to get to 25K feet.

[Discorde]

Thanks for your input FCeng84. The difficulty with the '25k within two minutes' requirement is the congested airspace in many regions of the world. In the worst case scenario rapid descent before or without ATC authorisation could lead to collision, which would clearly be more hazardous than hypoxia amongst some pax. TCAS in RA mode might give inappropriate commands and in TA mode might not give sufficient data to avoid conflict at very high descent rates. Unless there has been a change in policy, the 757/767 QRH also requires restricting airspeed if airframe damage is suspected (my highlighting).

http://steemrok.com/757depresschecklist

[VJW]

Perhaps I'm reading these replies wrong, and call me picky, but why are so many people (Pennellino, PENKO, JW411 and even I-2021) talking about descending to FL100? It's 10000 feet people! PENKO perhaps it's your licence which needs looking at :=

DOVES what are you on about with 14000'? That's the cabin altitude the masks automatically drop down if the altitude inside raises that high. It's not the altitude you descend to during an emergency decent.

[captplaystation]

Discorde,
Just a quick thanks for the link to "How to do well in the Sim", never seen that before & a quick glance suggests it is a thought provoking & well thought out piece, Cheers for that :ok:

[Discorde]

You're welcome!

[Domi]

Interim Report : http://www.bfu-web.de/cln_030/nn_1198882/EN/Publications/Interim__Reports/IR2012/I1__Report__12__FX003__B737__Lugano,templateId=raw,property= publicationFile.pdf/I1_Report_12_FX003_B737_Lugano.pdf

Very good maintenance :E

Ryanair blablabla :ok:

[de facto]

How expeditious does the descent need to be after loss of cabin pressure? There will be at least 10 minutes' worth of oxygen for pax and crew (and probably more for the pilots). A quote from 'How To Do Well In The Sim':

Quick enough so summer holidays pax dont get frost bite:eek: