Orient Thai Airlines clarifies its emergency landing

[tigermonkey]

Now what could have caused a sudden change in cabin pressure? Faulty door seal? Maintainence issue?

Was ICAO correct?

Several things can cause this but based on sketchy reports it was the system from an engine to the cabin which has several parts and functions. This wasn't catastrophic decompression and I doubt it had to do with seals etc.

There is what they call an air bleed from an engine which provides the air. That air is then filtered, dehumidified if needed and temperature adjusted. Remember it is way below freezing up there.

I don't know a thing about working on those parts between the engine and the cabin so I'll tell you what I've always been taught. The air bleed from the engine is just a supply and after the air is processed as listed above there is still a pump to pump it into the cabin and create the final pressure. There are also controlled outlets for circulation to keep the air fresh and supplied with new air and oxygen.

On some planes what they call the air bleed could also have the pump and push the air through everything after pressurizing it. I don't even know which system is most common but it could be that the pump driven by and at the engine is common.

If I'm wrong about any of that someone will correct me, but basically that's how it works and I believe something failed in that system.

There are many, many places that cabin pressurization can fail in a passenger aircraft, and this creates an alarm on the flight deck, that cabin altitude is too high ( above 10,000 to 12,000 feet). It's not an uncommon event, unless the depressurization is sudden. Standard procedure is to quickly, but not dangerously proceed to 10,000 feet or lower, and then land at the closest suitable airport. All modern passenger jets ( and turboprops ) use bleed air to supply the cabin air, except the Boeing 787 Dreamliner.

Edited April 1, 2015 by tigermonkey

[AleG]

Several things can cause this but based on sketchy reports it was the system from an engine to the cabin which has several parts and functions. This wasn't catastrophic decompression and I doubt it had to do with seals etc.

There is what they call an air bleed from an engine which provides the air. That air is then filtered, dehumidified if needed and temperature adjusted. Remember it is way below freezing up there.

I don't know a thing about working on those parts between the engine and the cabin so I'll tell you what I've always been taught. The air bleed from the engine is just a supply and after the air is processed as listed above there is still a pump to pump it into the cabin and create the final pressure. There are also controlled outlets for circulation to keep the air fresh and supplied with new air and oxygen.

On some planes what they call the air bleed could also have the pump and push the air through everything after pressurizing it. I don't even know which system is most common but it could be that the pump driven by and at the engine is common.

If I'm wrong about any of that someone will correct me, but basically that's how it works and I believe something failed in that system.

Just to be nitpicky...

Bleed air comes from one of the compression stages on the engine, so it's already pressurized and hot, no need for pumps to bring it into the cabin and it needs to be cooled or else the passengers and crew get toasty in there, and by toasty I mean well done.

[tigermonkey]

I was on 737 old series once and one engine had to be shut down for some technical reason. No sudden drop, nosebleeds etc. Just a fairly normal landing at nearest airport where emergency crews were on standby.

It wasn't a Oriant Thai plane though, was it??

Nope but this 737 was so old had wooden fold up trays lol

Was that Air India Regional ? They have a number of 737's in service that are 35 years old. There are probably older 737 airframes somewhere, but anything over 25 years is beyond scary.

[tigermonkey]

A sort of bonus for flying that airline, a free side trip ?

Decades ago i flew Garuda from Jakarta to Denpasar and en route the pilot announced if passengers looked out the port windows we would see the crater of a dormant volcano. He then announced that since we had time in hand he would give us a closer look so he lost altitude and circled the volcano before returning to the original, and proper, flight path.

Some of the looks on faces were priceless and I wonder what those looks would be like nowadays with all that's happening in the airline industry.

I took his word for the fact the volcano was dormant and just hoped it was.

Nice.....But Garuda....I fly with them twice and the airplane looked like it was still the same you used decades before........

Heavy "Diesel" (whatever it was) smell inside. Really very strong.

Very strong vibrations from the engines.

aircon filled the room with fog, that much that you can't see much anymore.

uniforms from the stewardess looked like it was second hand bought from East Germany.

Everyone got a little water only.

Inside it looked very old

Most probably the airplane was fit, but these things let it appear different.

You were probably smelling what Americans call kerosene and a refining of it called Jet A. It's just about one step above diesel when cracking a barrel of oil. It is standard jet fuel and quite smelly.

yes.....But the smell was like they spilled a liter inside the cabin (my nose isn't sensitive, I smell things long after other people)....I guess they spilled a bit outside and in the Indonesian heat it evaporates faster. But still it makes the passenger afraid.....Some looked uncomfortable.........

Maybe moving the machine 10 meter and put a fan inside for 5 min would have fixed it (machine wasn't cool inside anyway).

It was much less likely to be fuel, than lubricant leakage from an engine. Pressurized air is supplied to the cabin from a compressor stage of the engines; if the oil seals are old/worn then oil seeps onto the cabin air system, where it is vaporized into the cabin air. On occasion, on start-up, there is enough oil to cause the air conditioner packs to create a fog throughout the cabin and flight deck. It is much less of a problem now than it was, since it has become very much a known problem'

If you want to know more, Google 'Aerotoxic Syndrome'

[MiKT]

Drop in air pressure?? Somebody must have opened a door to use the outside loo

Absolutely, Chinese passengers, drop in pressure, open door, elementary my dear Grandtee, elementary.

[Chao Lao Beach]

If the masks droped the cabin preasure was decreasing hence a fast controlled decent to the lower safe or an alt of 10,000 - 14,000 feet is normal for this situation. Clearly OT is ful of garbage.

[trogers]

I was on 737 old series once and one engine had to be shut down for some technical reason. No sudden drop, nosebleeds etc. Just a fairly normal landing at nearest airport where emergency crews were on standby.

It wasn't a Oriant Thai plane though, was it??

Nope but this 737 was so old had wooden fold up trays lol

Was that Air India Regional ? They have a number of 737's in service that are 35 years old. There are probably older 737 airframes somewhere, but anything over 25 years is beyond scary.

Read about the explosive decompression of Aloha Airlines 243 due to metal fatigue of the airframe. That was also an old 737 plane.

[gchurch259]

I wonder what the average Aviation Experience, either Maintenance or Pilot, is of all those who post their opinions before all the facts are released.

I also wonder where in the Hell the Media gets some of their reporters ?

[Skywalker69]

Drop in air pressure?? Somebody must have opened a door to use the outside loo

A chinese whom wanted to pee?

[Suffinator]

Defending the flight on its Facebook page, Orient Thai Airlines said its pilot and flight attendants have strictly abided by the aviation safety measures.

Does that include the strict safety measures that need comply with by the UN?

So the pilot had to perform an emergency landing where no emergency was present?

Seriously you couldn't make this up.

I see many people posting here saying they wouldn't fly with Thai Orient (formally 1-2-Go but changed after the fatal crash at Phuket). Personally I would get on any aircraft operated by a Thai carrier. Considering their obvious care for the safety and that they are more than willing to sweep such under the nearest rug is just asking for trouble.

[Moonlover]

^{Like most other aviation professionals I despair at the inaccurate and sensationalist reporting of aviation incidents and accidents. My advice is to believe about1% of what you read or view and see on TV, including comments by some of the so called experts. Mind you some of the comments here are equally uninformed and sensationalist.}

^{A loss of pressure requiring descent is not all that uncommon. I have been on 2 flights in Australia (Qantas and the old Ansett) when this has occurred - no associated engine failure and everyone eventually put on their masks until it was OK to remove these below 10000 ft - no panic by anyone.}

^{I do not know what the cause of the depressurisation was on the Orient Thai flight, but it appears to have been well handled and a safe outcome was achieved. If pressurisation was the only problem then there was NO emergency landing. In my Air Traffic Controller experience the Rescue and Fire Services would not even been alerted in these circumstances.}

^{A few words about loss of pressurisation. As part of the pre flight checks the pilots with check their oxygen system, and in the event of depressurisation will put on their masks first thing, then commence descent to 10000 ft or the minimum safe altitude in high terrain areas, release the passenger masks (these will normally deploy automatically) call ATC and then coordinate with the flight attendants. If you are a passenger get those masks on immediately. If the flight is at 41000 ft (not uncommon these days) and there is a rapid decompression, then the time of useful consciousness is between 5 and 10 seconds - even shorter if you are a smoker, unhealthy, very old or very young. So there is not much time to keep yourself usefully alive until the aircraft is below about 15000 ft.}

Thank you Bra for your professional input. It was quite obvious from yesterday's report that it was the result of, shall we say, over enthusiastic reporting!

I'll add one small point that you have not mentioned, that is the nose bleeds. There is nothing unusual, or alarming about this. When the cabin pressure falls rapidly, the sinus' decompress rapidly. They are not used to this and it often results in the blood capillaries busting and bleeding into the nose and possibly mouth. The two are interlinked of course. SCUBA divers occasionally suffer this as well during ascent. A mask full of blood can be an alarming sight, but there is no resulting harm.

Maybe the 'barstool aviators' will calm down, now that a bit of common sense has been injected into this topic.

[mjcmjc]

"dismissed a report that its flight OX682 from Phuket to Chengdu had made emergency landing at Kunming airport, saying it landed normally and safely with no passengers injured"

If nothing went wrong, why did it land in Kunming, rather than its destination Chengdu.

So it's normal to land at the wrong airport with oxygen masks deployed.

[Pimay1]

Passenger Lixue Ku, 47, told Daily Mail people were screaming and crying as they feared the plane would break apart in the sky or crash.

"I kept thinking about that plane crash in France, and I was convinced we were going to go the same way, but then the plane evened out," he said. "Everyone was in shock, even the staff."

Who do you believe, the airline or this passenger? I believe the passenger.

[Shiver]

People pay good money for adrenaline rush extreme sports. TAT should exploit this.

If they can get Stephen Hawking in a jump suit with his computer speaking in monotone "yahoooo!" that would be bonus points.

Unbuckle your seat belts, you're about to experience zero G.

Edited April 1, 2015 by Shiver

[Ricardo]

"dismissed a report that its flight OX682 from Phuket to Chengdu had made emergency landing at Kunming airport, saying it landed normally and safely with no passengers injured"

If nothing went wrong, why did it land in Kunming, rather than its destination Chengdu.

So it's normal to land at the wrong airport with oxygen masks deployed.

Normal perhaps, for this airline, not normal elsewhere IME.

And if everything was fine, and there was no in-flight emergency (which the flight-crew handled properly), why put the passengers into a hotel in Kunming while awaiting the arrival of a replacement-aircraft to be sent from DMK ?

All passengers were checked into hotels for overnight stay and they were flown off the next day in another plane departing from Don Mueang airport. The plane landed safely at Chengdu at 5.30 pm (local time) on Sunday.

[Johnny S]

Never fly 1-2-go, sorry Orient Airlines - different name same sheit and still reporting lies when their plane are almost going down like in Phuket

Pay a Little more and dont use a Thai carrier

[Godders]

Why doesn't someone just ask the passengers?

[tigermonkey]

Passenger Lixue Ku, 47, told Daily Mail people were screaming and crying as they feared the plane would break apart in the sky or crash.

"I kept thinking about that plane crash in France, and I was convinced we were going to go the same way, but then the plane evened out," he said. "Everyone was in shock, even the staff."

Who do you believe, the airline or this passenger? I believe the passenger.

That would be one of my worst nightmares - being trapped in a confined space with a group of hysterical Chinese. .

[realenglish1]

Is that what the smell was and I thought my brother forgot deodorant

[kennw]

Some yeas ago was booked with two others to fly business class Jakata to Denpassa, Flight was delayed so told to wait in the busness lounge. Unfortunately still holding our boarding passes the plane left without us, but had our luggage on board. They calmly said never mind get the next plane in one hour. Bags were sitting un-attended on the terminal floor when we arrived. Things have greatly improved now.

[jacko45k]

I struggle to see how an aircraft can land normally at the wrong airport unless diverted.

[Gonsalviz]

Now what could have caused a sudden change in cabin pressure? Faulty door seal? Maintainence issue?

Was ICAO correct?

Several things can cause this but based on sketchy reports it was the system from an engine to the cabin which has several parts and functions. This wasn't catastrophic decompression and I doubt it had to do with seals etc.

There is what they call an air bleed from an engine which provides the air. That air is then filtered, dehumidified if needed and temperature adjusted. Remember it is way below freezing up there.

I don't know a thing about working on those parts between the engine and the cabin so I'll tell you what I've always been taught. The air bleed from the engine is just a supply and after the air is processed as listed above there is still a pump to pump it into the cabin and create the final pressure. There are also controlled outlets for circulation to keep the air fresh and supplied with new air and oxygen.

On some planes what they call the air bleed could also have the pump and push the air through everything after pressurizing it. I don't even know which system is most common but it could be that the pump driven by and at the engine is common.

If I'm wrong about any of that someone will correct me, but basically that's how it works and I believe something failed in that system.

Finally a voice of reason above the cacophony. There are check valves in bleed air lines. They can stick open and if the engine supplying that line quits, cabin air will leak out. They are big pipes (in the 15cm range). That alone could cause decompression and cause a mask drop.

[Bangkok Barry]

"dismissed a report that its flight OX682 from Phuket to Chengdu had made emergency landing at Kunming airport, saying it landed normally and safely with no passengers injured"

If nothing went wrong, why did it land in Kunming, rather than its destination Chengdu.

The report doesn't say that nothing went wrong. It said there was a loss of cabin pressure. Yet another example of TV users who can't read properly before engaging brain and writing nonsense.