AirAsia QZ8501 Missing
Discussion
carreauchompeur said:
Horrible.
As others have said, I was under the impression that AirAsia's fleet was very young- flew on them in 09 with no problems.
Without Googling, when was the last high profile aircraft crash directly attributable to the age of the airframe? People often seem to mention the age of the fleet, but I'm not sure how much relevance this has. As others have said, I was under the impression that AirAsia's fleet was very young- flew on them in 09 with no problems.
Air Asia's safety record is a little more complicated than calling it impeccable over the last 10 years. I haven't got the answers to my own questions and I'm too lazy to look, but generically?
1) How is their Flight Data Monitoring System? What trends has it identified?
2) What is their Flight Safety Plan going forward?
3) AF highlighted some issues with Unreliable Airspeed and Airbus types. How did Air Asia react to this? Did they incorporate a module in recurrent training to specifically address this? How was Pilot performance subsequently?
4) If they did make adjustments to their pilot training, how far through the syllabus is each pilot in the system? Have they all completed an updated training module based on the lessons from the AF accident?
No high profile accidents over the last 10 years does not an 'impeccable safety record' make. If everything is operating normally then it should be relatively straight forward for an airline to avoid a high profile incident. When you scratch beneath the surface you learn a little more about how an airline has prepared for the once in a career incidents. I mean things like:
1) Controlled Flight Into Terrain
2) Unreliable Airspeed
3) Runway Undershoots/Overruns. 4) etc
The lack of a hull loss is also mentioned as making Qantas a good carrier to choose. But, people aren't choosing them; they're abandoning them. Captains are being demoted, First Officers are becoming Second Officers again and they haven't hired any new pilots since 2009 IIRC. If I believe what I've read then money is being diverted into their low cost start up, Jetstar, and Qantas appears to be being run down. The currency when choosing an airline isn't safety it's increasingly solely price. I think that safety is often taken as a given, for a variety of factors, when it's anything but.
My points are generic and unfortunately it's Air Asia who are in the spotlight now. It's impossible to pass any judgement on how safe any airline is until you can provide some answers to any of the points above and more. I've no idea where Air Asia fits into this spectrum.
Phew.
Edited by pushthebutton on Sunday 28th December 15:02
Interesting read on the weather situation in the very area the plane was flying through prior to it going off the radar.
http://www.weathergraphics.com/awq8501/
http://www.weathergraphics.com/awq8501/
Scuffers said:
TVR1 said:
Qantas are playing semantics with that one though. Their USP is never having suffered a hull loss in a jet aircraft as a result of an accident.
Qantas VH-OJH 747 into Bangkok should have been a write off but wasn't. Repaired at a cost approaching $100m. Value at the time was $85m IIRC. There was No Way Qantas was suffering a hull loss. AFAIK, it's still sitting at a hanger in Bangkok.
http://aviation-safety.net/database/record.php?id=...
don't disagree with the point, but that plane did fly again, was used till 2012, last passenger flight was Johannesburg - Sydney as QF64 - September 3 - 4, 2012, flown to Marana as QF6019 for storage - October 4, 2012, deregistered from Australian Aircraft Register - November 20, 2012, finally scrapped at Marana - 2013.Qantas VH-OJH 747 into Bangkok should have been a write off but wasn't. Repaired at a cost approaching $100m. Value at the time was $85m IIRC. There was No Way Qantas was suffering a hull loss. AFAIK, it's still sitting at a hanger in Bangkok.
http://aviation-safety.net/database/record.php?id=...
kapiteinlangzaam said:
Eric Mc said:
kapiteinlangzaam said:
Commercial pilots will not fly over active TS systems.
Sorry, I thought that was clear from the one word reply.
OK - but they will try to go around thunderstorms. I used to listen to ATC a lot and you would often hear pilots asking for courses to avoid weather build ups. This plane seemed to be in the process of doing this.Sorry, I thought that was clear from the one word reply.
iphonedyou said:
Scuffers said:
statistically it does.
The Qantas thing is about never losing a jet aircraft (as in crashing one), last hull loss they had was a de Havilland DHA-3 in 1951.
QF32 is probably the closest they have come to losing a plane.
Statistically it definitely doesn't.The Qantas thing is about never losing a jet aircraft (as in crashing one), last hull loss they had was a de Havilland DHA-3 in 1951.
QF32 is probably the closest they have come to losing a plane.
http://en.m.wikipedia.org/wiki/Gambler%27s_fallacy
RIP, terrible
The only possible link you could have is if airlines never retired their planes. The more hours they accumulated (by not crashing), the more likely it is that one of them would crash from fatigue or some other such flight cycle related problem. But airlines renew their fleets for that exact reason.
Grumfutock said:
Petrus1983 said:
Wreckage reportedly has been found east of Belitung Island. A sad day indeed.
Here's a picture of the weather map in the area at the time -
Where are these reports? No news of any discovery yet?Here's a picture of the weather map in the area at the time -
Petrus1983 said:
Grumfutock said:
Petrus1983 said:
Wreckage reportedly has been found east of Belitung Island. A sad day indeed.
Here's a picture of the weather map in the area at the time -
Where are these reports? No news of any discovery yet?Here's a picture of the weather map in the area at the time -
Super Slo Mo said:
Mojocvh said:
Super Slo Mo said:
sebhaque said:
djc206 said:
MitchT said:
I went to Munich in May on an A319 and we flew at 39,000 the whole way. It's it really a big deal for an A320 to be flying at 38,000?
No I've worked dozens myself this morning. Perfectly routineThat is, of course, groundspeed, not airspeed, which could have been significantly different.
Edited by Super Slo Mo on Sunday 28th December 13:38
At 350 kts however, it is very high, possibly very close to being outside of the operating envelope of the aircraft...
Gotta wonder at the "call search off for night" as it is quite close to land @30 miles? don't think if it was an initial survivable event this action will have helped.
350 kts is misleading. The Airspeed Indicators will normally read 250kts + /- 20kts either side in normal cruise. In a 320 type aircraft an IAS of 250kts may well convert to a True Air Speed of 420 kts and a 70 kt headwind will result in a Ground Speed of 350 kts. In this case the figures aren't particularly alarming
Working backward however, a Ground Speed of 350 kts with fairly slack winds at 36'000ft may translate to a lower than desired Indicated Airspeed. It is this airspeed on which the parameters of flight are based. If this figure (IAS) is too low then the aircraft is closer to the stall.
The above is simplified because I can't see any point in complicating it. If 350 kts was the recorded GS of the aircraft, then, with slack winds, it points towards a lower than ideal IAS at ~ 36'000ft. Think of IAS purely as the rate at which the air molecules are striking the aircraft. In denser air (lower) there are more molecules and in thinner air (higher up) there are fewer. However the Pitot tubes will only measure the total molecule strikes. At low levels IAS can be close to TAS, but at higher levels your true speed through a given block of air is higher than your instruments indicate.
Working backward however, a Ground Speed of 350 kts with fairly slack winds at 36'000ft may translate to a lower than desired Indicated Airspeed. It is this airspeed on which the parameters of flight are based. If this figure (IAS) is too low then the aircraft is closer to the stall.
The above is simplified because I can't see any point in complicating it. If 350 kts was the recorded GS of the aircraft, then, with slack winds, it points towards a lower than ideal IAS at ~ 36'000ft. Think of IAS purely as the rate at which the air molecules are striking the aircraft. In denser air (lower) there are more molecules and in thinner air (higher up) there are fewer. However the Pitot tubes will only measure the total molecule strikes. At low levels IAS can be close to TAS, but at higher levels your true speed through a given block of air is higher than your instruments indicate.
Edited by pushthebutton on Sunday 28th December 17:59
Grumfutock said:
Thank you, just wondered as I couldn't find any. And yes very sad.
Yep, just checked again and you're right, the early reports have gone - although still showing on the RT 'feed' but things have progressed. Not sure about anyone else but I think this is the first year where flying has become a bit strange again for quite a while - 2 missing planes and another blown from the sky over a warzone - not including the 'every day' accidents. OK, with my QFI hat on:
There seems to be a certain amount of confusion in this thread WRT to ‘Airspeed’, with claims that 350kts G/S (Groundspeed) are either too close to Vs (Un-accelerated Stall Speed, ie straight and level flight, clean Flaps and Gear UP) or to Vmo/Vne (Maximum Operating speed/Never Exceed speed).
G/S itself has no direct relationship to Indicated Air Speed (the relationship is complex and relies upon air density, ie altitude and temperature), but does have a direct relationship with TAS (True Air Speed). Indicated Air Speed (IAS) is itself somewhat misleading since it will be a factor of Instrument Error (ie things like non-linearity and ‘stiction’ in the instrument) as well as Pressure Error caused by the position of the Pitot and Static Vents as well as any shockwave formation as the airflow over the a/c becomes transonic). For future comment I will use the term KCAS (Calibrated Airspeed in Knots) which takes account of these errors, but for the non-fliers (as well as the PPL holders) you can consider KCAS to be the same as IAS.
However, G/S while directly related to TAS is also affected by W/V (wind velocity). If you have a wind on the nose, then for any given TAS your G/S will be lower and vice versa.
So, firstly we do not know what the wind was doing in this scenario. Secondly we have no idea of the temperature structure of the atmosphere in that region at that time. Thus all we can do is make a few educated guesses.
Given that we have no W/V data, then the first assumption is that the a/c was operating in ‘Still Air’. If that was the case then the G/S would be exactly the same as the TAS. Thus the TAS at FL380 would be 350kts.
The next problem is that, not knowing the temperature structure of the atmosphere, we have no accurate idea of just how high FL380 actually is. Flight levels are based upon a std altimeter setting of 1013.25mb so their actual altitudes above sea level vary dependent upon atmospheric conditions. All we can do here is assume that the conditions are ISA (International Standard Atmosphere) such that FL380 = 38,000ft. In reality there could be quite a large variation here.
The third problem is that, not knowing the temperature structure of the atmosphere, we cannot directly work out KCAS from TAS, all we can do is a series of calculations in order to give a broad brush picture.
So:
1. Assuming still air and that 350kts G/S = 350kts TAS.
2. Assuming FL380 = 38,000ft
Then, using my trusty Dalton Computer to calculate the KCAS I get the following:
ISA conditions (Sea Level air pressure of 1013.25 mb, Sea Level air temp of +15C, Adiabatic lapse rate of 1.98C per 1000ft), a TAS of 350kts = a KCAS of 185kts
ISA +10 : KCAS = 180kts
ISA +20 : KCAS = 175kts
ISA –10 : KCAS = 188kts
ISA –20 : KCAS = 195 kts
I’ve never flown an Airbus, nor do I have access to the ODM (Operating Data Manual), I’m also fully cognisant of the fact that there is an increase in Vs in terms of KCAS with altitude for any given all up weight. However I would have thought that a KCAS of 180-195 kts would be well above the un-accelerated Stall Speed.
With regard to Vno/Vne then this will be based upon KCAS at low level and Mach No (Mno/Mne) at high level.
Using the same assumptions as above, then we get Mach Nos of:
ISA : 0.6
ISA +10 : 0.59
ISA +20 : 0.575
ISA -10 : 0.615
ISA -10 : 0.63
I would suggest these Mach Nos are way away from the airframe limit!
Having done these calculations I would further suggest that the assumption of ‘still air’ is way wide of the mark and that the a/c was encountering a fair headwind.
There seems to be a certain amount of confusion in this thread WRT to ‘Airspeed’, with claims that 350kts G/S (Groundspeed) are either too close to Vs (Un-accelerated Stall Speed, ie straight and level flight, clean Flaps and Gear UP) or to Vmo/Vne (Maximum Operating speed/Never Exceed speed).
G/S itself has no direct relationship to Indicated Air Speed (the relationship is complex and relies upon air density, ie altitude and temperature), but does have a direct relationship with TAS (True Air Speed). Indicated Air Speed (IAS) is itself somewhat misleading since it will be a factor of Instrument Error (ie things like non-linearity and ‘stiction’ in the instrument) as well as Pressure Error caused by the position of the Pitot and Static Vents as well as any shockwave formation as the airflow over the a/c becomes transonic). For future comment I will use the term KCAS (Calibrated Airspeed in Knots) which takes account of these errors, but for the non-fliers (as well as the PPL holders) you can consider KCAS to be the same as IAS.
However, G/S while directly related to TAS is also affected by W/V (wind velocity). If you have a wind on the nose, then for any given TAS your G/S will be lower and vice versa.
So, firstly we do not know what the wind was doing in this scenario. Secondly we have no idea of the temperature structure of the atmosphere in that region at that time. Thus all we can do is make a few educated guesses.
Given that we have no W/V data, then the first assumption is that the a/c was operating in ‘Still Air’. If that was the case then the G/S would be exactly the same as the TAS. Thus the TAS at FL380 would be 350kts.
The next problem is that, not knowing the temperature structure of the atmosphere, we have no accurate idea of just how high FL380 actually is. Flight levels are based upon a std altimeter setting of 1013.25mb so their actual altitudes above sea level vary dependent upon atmospheric conditions. All we can do here is assume that the conditions are ISA (International Standard Atmosphere) such that FL380 = 38,000ft. In reality there could be quite a large variation here.
The third problem is that, not knowing the temperature structure of the atmosphere, we cannot directly work out KCAS from TAS, all we can do is a series of calculations in order to give a broad brush picture.
So:
1. Assuming still air and that 350kts G/S = 350kts TAS.
2. Assuming FL380 = 38,000ft
Then, using my trusty Dalton Computer to calculate the KCAS I get the following:
ISA conditions (Sea Level air pressure of 1013.25 mb, Sea Level air temp of +15C, Adiabatic lapse rate of 1.98C per 1000ft), a TAS of 350kts = a KCAS of 185kts
ISA +10 : KCAS = 180kts
ISA +20 : KCAS = 175kts
ISA –10 : KCAS = 188kts
ISA –20 : KCAS = 195 kts
I’ve never flown an Airbus, nor do I have access to the ODM (Operating Data Manual), I’m also fully cognisant of the fact that there is an increase in Vs in terms of KCAS with altitude for any given all up weight. However I would have thought that a KCAS of 180-195 kts would be well above the un-accelerated Stall Speed.
With regard to Vno/Vne then this will be based upon KCAS at low level and Mach No (Mno/Mne) at high level.
Using the same assumptions as above, then we get Mach Nos of:
ISA : 0.6
ISA +10 : 0.59
ISA +20 : 0.575
ISA -10 : 0.615
ISA -10 : 0.63
I would suggest these Mach Nos are way away from the airframe limit!
Having done these calculations I would further suggest that the assumption of ‘still air’ is way wide of the mark and that the a/c was encountering a fair headwind.
Ginetta G15 Girl said:
Having done these calculations I would further suggest that the assumption of ‘still air’ is way wide of the mark and that the a/c was encountering a fair headwind.
I think that the winds were fairly slack and a couple of published charts and flight plans for the region back that up. The aircraft was also not too far from the Equator which isn't known for its strong upper level winds. Accepting that strong Cb activity may have a local affect on the instantaneous wind;if the GS was as shown by the flight tracking app then it is approaching abnormal. Thanks for that, I had no access to the upper wind charts for that region.
Given that there were reported slack winds, and aside from any localised Cb effect, it does rather raise the Q as to why IAS/Indicated Mach would be allowed to get so low.
Given that there were reported slack winds, and aside from any localised Cb effect, it does rather raise the Q as to why IAS/Indicated Mach would be allowed to get so low.
Edited by Ginetta G15 Girl on Sunday 28th December 22:42
cossy400 said:
Bbc sayin search called off. For the time being.
Yes but only due to daylight and weather conditions. Resuming pretty much about now. I guess the best guess at present is that the plane was somehow a victim if the weather, but I do hope they find the wreckage - not just for the relatives, but if this one doesn't show up, the airlines and the governments are going to have a real headache on their hands, and the conspiracy theorists are going to beat themselves off into oblivion.
Pesty said:
Followed two other planes who went through the same area. Would they have reorted heavy weather?
It's quite a busy route, lot of traffic there everyday, including all northbound Australia-Singapore/Thailand/Malaysia flights. They usually overfly Bali then skim over Surabaya and onto Singapore. Weather should be well known Gassing Station | News, Politics & Economics | Top of Page | What's New | My Stuff