Air Asia Indonesia Lost Contact from Surabaya to Singapore

[Volume]

The problem with items 2 and 3 of your “5 ways to crash” is that the airplane doesn’t stall unless there is some kind of systems failure, such as clogging of pitots or freezing of AoA sensors.

I would not state it that way, Pulkovo 612 tells us a different story:

Based on various information, including the partially decrypted from a recovered flight recorder, crash investigators believe that the aircraft climbed to an altitude higher than the maximum for which it was designed, causing the aircraft to enter into a flat spin from which it never recovered.

Interstate Aviation Committee after initial decoding of flight recorders data issued the following flight safety recommendations: avoid entering thunderstorms, follow all maximum height limitations based on aircraft load and outside air temperature, and to improve pilot training when working in these situations.

I think IAC nailed it down quite perfectly...

[Sop_Monkey]

These knee jerks, is a classic illustration of the calibre of the authorities. Next will be astronaut medicals 4 per year instead of 2. As if we dont have enough rubbish to contend, preflight. Soon our preflight duties will put us out of hours before we even get airborne. Total nonsense.

[p.j.m]

Originally Posted by Sop_Monkey

These knee jerks, is a classic illustration of the calibre of the authorities.

and on it goes....

AirAsia banned from key routes amid government crackdown

AirAsia has been banned from flying five of its key Indonesian domestic services out of Surabaya airport as part of a government crackdown on previously unenforced regulations in the wake of the crash of flight QZ8501.


The bans on the flights - three from Surabaya to the capital, Jakarta, one to Bali and one to regional centre Bandung - will deal another blow to the Malaysia-based low-cost carrier, which had already been suspended from the Surabaya-Singapore route entirely.


It's part of a broader government crackdown on lax administration of flight permits from Surabaya Airport. The fast-growing Indonesian-owned low cost carrier Lion Air has been stopped from flying nine of its weekly services, and smaller aircraft Trigana and KalStar have also been affected.


And late on Tuesday, another airport, Medan, made a similar decision, banning AirAsia from flying its Tuesday Medan to Palembang service.

Seems to be yet another example of Indonesian authorities cutting off their nose, to spite their face. The only losers here are the Indonesian people and businesses.

[langleybaston]

Quote:
In a 14-page report, the Indonesian weather office said engine damage due to ice was “the most probable weather phenomenon” at play in the crash of the Airbus A320-200, which had 162 on board.

As a retired but fully qualified MoD Principal Scientific Officer meteorologist, I wonder how on earth does the Indonesian equivalent think it is even remotely qualified to speculate?

Their task is to:

record and disseminate the actual weather

predict the weather

disseminate predictions.

Secondary tasks might be to:
provide climatology
conduct research

Beyond that, speculation that ice was “the most probable weather phenomenon” is at best a hostage to fortune, at worst downright misleading.

If, God forbid, a similar accident occurred under UK jurisdiction, the Met. Office would not be speculating in public, or, if it did, would be kicked to bits by the various aviation authorities.

I hope!

[Gysbreght]

Machinbird,

I agree that a crash site not far from LKP may indicate a sustained stall, though not necessarily from cruise altitude. However, as you know, the plane with all system components operating as designed is well protected against stalling. So how could the airplane be stalled at altitude?

One obvious possibility is that the pitots became obstructed with ice crystals, airspeed indications were lost, FCS reverted to alternate law without stall protection, pilot pulled up into a stall and maintained it until impact, as in AF447. However, in view of the extensive publicity that accident has received, it is almost unbelievable that it was repeated.

The sequence that I have in mind starts here:

The aircraft was observed on ATC radars to both climb and to decelerate (GS) significantly before descending rapidly.

That observation is consistent with an encounter with an upward gust, that momentarily increased the AoA to beyond alphaprot, and put the Flight Control System (FCS) in high-angle-of-attack protection mode. When that happens, the FCS maintains an AoA equal to alphaprot, until the pilot moves the sidestick forward (or some other criterion is met). The result is that the airplane enters a steep climb at the expense of airspeed, levels off, then starts to descend. The cited A340 incident started at FL350, M.84, reached FL380, M.66, 205 kCAS, and max RoC was about 6000 fpm. About 100 seconds after the upset the pilots moved the sidestick forward and resumed normal flight. During that time crew changed parameters of the disconnected autopilot and evidently did not understand what was happening. Although the lowest speed came close to the stall speed, there never was a risk of stalling, as long as the FCS remains in Normal Law.

The high-AoA protection is lost when the FCS reverts to Alternate Law when certain system components fail or are switched off.

The emergency procedure that I refer to is quite recent, the EASA EAD is dated 9 December 2014 and demands compliance within 2 days after receipt. The background states:

When Alpha Prot is activated due to blocked AoA probes, the flight control laws order a continuous nose down pitch rate that, in a worst case scenario, cannot be stopped with backward sidestick inputs, even in the full backward position. If the Mach number increases during a nose down order, the AoA value of the Alpha Prot will continue to decrease. As a result, the flight control laws will continue to order a nose down pitch rate, even if the speed is above minimum selectable speed, known as VLS.
This condition, if not corrected, could result in loss of control of the aeroplane.

Possibly the pilots have taken notice of the change just a few days before the accident flight and, being kept very busy, not given it more than cursory attention. IOW, they may not have fully appreciated and remembered the precise system failure scenario behind that procedure. If the high-AoA protection mode was was triggered by a gust, they may well have been as surprised and confused as the crews in the A330/A340 ‘level bust’ incidents. They may have remembered the recently introduced procedure and switched off 2 ADR’s, losing the stall protection, and stalled during the recovery from the upset.

That may all seem rather far-fetched, but is it possible?

[Flagon]

"The aircraft was observed on ATC radars to both climb and to decelerate (GS) significantly before descending rapidly." - fact or fiction?

[Ian W]

Originally Posted by BG47

@ Training Wheels, according to the press the reason for the schedule change of AirAsia’s scheduled flights on Sunday was because of Singapore not Indonesia/AirAsia. Singapore stated that Indonesia as a whole was reaching their immigration quote limits into their country. AirAsia’s Sunday flights were canceled on the paperwork from Oct 2014 to March 2015. The news article did not state if other airlines were affected or not by this Singapore immigration quote limit. The press is asking Indonesia questions but not with Singapore, would be good to know if Singapore indeed limited the flights.

Here is the Fox News Article:

Just a thought - if the flight takes off at 23:00UTC - 06:00LT is it a Saturday flight or a Sunday flight? Could this be the real reason for the change in flight time to 2 hours earlier to arrive late Saturday before midnight UTC?

[threemiles]

It's been said before that flights from SUB were declustered from the 6 a.m. departure peak, so that everybody had a chance to get the airplane into the air in time and not screw up the day's schedule from the beginning with an hour start-up delay.

There is much too much emphasis on this early departure and Sunday's not allowed stuff. It is just political and journo bs*** but is totally irrelevant to the cause of the accident.

[Lost in Saigon]

Originally Posted by Flagon

"The aircraft was observed on ATC radars to both climb and to decelerate (GS) significantly before descending rapidly." - fact or fiction?

Fact.....

[HotDog]

It is not Air Asia or Trigana etc. that should be penalised for apparently operating a flight without a permit. How did Surabaya Airport accept the flight plan and how did the aircraft receive permission for take off from Surabaya tower? Surabaya seems a dodgy place to operate from, nearly caused a CX A330 serious accident by uplifting contaminated fuel for a flight to Hong Kong not so long ago, which was only saved by the skill of the flight crew. No wonder Indonesian air operation audit is one of the lowest in the world with many Indonesian operators banned from flying in EU airspace. I understand that this had nothing to do with the loss of the aircraft but perhaps it wouldn't have happened if they refused to clear the flight that day?

[sunside]

I don't see it "descending rapidly" on that radar image

[Lost in Saigon]

Originally Posted by sunside

I don't see it "descending rapidly" on that radar image

No one has seen radar screenshots of the descent but it has been reported by AirNav Indonesia.



06:12

- QZ8501 requests left deviation from airway. Deviation approved.
- Pilot then requests climb to FL380
- ATC asks pilot to standby, due to nearby traffic and to coordinate with next sector (Singapore)

06:14

- ATC calls QZ8501 to approve climb to FL340
- No response received after 2 or 3 further attempts to contact
- ATC requests help from nearby aircraft to contact QZ8501

06:16

- ATC still cannot reach QZ8501
- Aircraft still observed on radar screen

06:17

- Radar contact lost
- Last reported altitude: FL290

[mcloaked]

In the last day or so the American Navy have positioned USS Fort Worth in the Java Sea, and are using a Tow Fish side scan sonar system. This may yet provide higher quality sonar imagery for areas where suspected large parts of the aircraft have been tentatively identified but not yet confirmed. Does anyone here know if the US also have the simultaneous provision to detect pinger signals with this system?

[ohnutsiforgot]

Rapid Up and Down

Perhaps we should keep in mind the hysterical speculation following the GOL-Legacy crash in Brazil, which was followed by speculation that the Legacy was stunting, climbing and desending wildly, etc.. which turned out to be an interpretive issue with Brazilian radar.

[Livesinafield]

I didn't know the last level seen on SSR was 290, if that's the case something severe must have happened to cut the power, would be interesting to see any PSR shots

[Flagon]

LIS - are the source/time/date of your 'reports' officially substantiated? Remember they are Mode C readings as well. Someone previously here cast doubt on the track displayed too. Whether that post still exists........? What explanation did your 'source' have for '353'?

[slats11]

I wonder if recent attention from ICAO is an explanation for the tough posturing of Indonesian authorities.

Some years ago there was concern that Australia's regulator (CASA) wasn't sufficiently resourced to carry out its functions. It may have been coincidence, but shortly after this CASA took a very tough line temporarily grounding an airline.



ICAO Secretary General Conducts Official Visits in Indonesia

MONTREAL, 3 December 2014 – ICAO Secretary General Raymond Benjamin was in the Republic of Indonesia earlier this month, where he held high-level discussions with local officials, including the Minister of Transportation, H.E. Ignasius Jonan, the Minister of Foreign Affairs, H.E. Retno L.P. Marsudi, the Acting Director General of Civil Aviation, Bambang Tjahyono, and other high-ranking members of the Indonesian Government.

Benjamin spoke during the Opening Ceremonies of the ICAO Air Service Negotiation Event (ICAN 2014) which took place this year from 17–21 November 2014 in Bali. The meeting was also addressed by the Minister of Transportation of Indonesia, the Acting Director General of Civil Aviation, and the Executive Director for Operational Programmes and Institutional Relations of the World Tourism Organisation (UNWTO), M. Favilla L. de Paula.

Indonesia Struggles With Air Safety Oversight - WSJ

Despite more than seven years of concerted international help to improve the Indonesian government’s air-safety oversight, its system still ranks among the worst in national audits conducted by a United Nations agency.

Countries that have been scored higher by the International Civil Aviation Organization on the overall effectiveness of their aviation laws, regulations and monitoring efforts include tiny players such Albania, Kyrgyzstan, Cameroon and Burkina Faso.

Regulators in Jakarta now oversee a global aviation powerhouse with domestic airlines operating nearly 400 jets—carrying more than 50 million passengers annually—but results of the country’s latest ICAO audit are more comparable with those for Guinea or Latvia, nations with limited aviation activity.

In a statement Monday, Indonesia’s Transport Ministry said “it’s not true that Indonesia is one of the world’s most hazardous in terms of aviation.” The statement also said airlines “are required to have internal quality and safety inspectors licensed by” regulators, who perform “routine and periodic audits every two years, and surveillance every month.”

[training wheels]

Originally Posted by Lost in Saigon

Fact.....

The time that this event occurred (the excursion to FL363) can be estimated if someone can work out from Flightradar24, the time that EK409 was at the position in the radar screenshot. Presumably it will be some time between 0612 and 0617. From there, you can work out its estimated rate of descent if its confirmed that it passed through FL290 at 0617.

[Ian W]

Originally Posted by Flagon

LIS - are the source/time/date of your 'reports' officially substantiated? Remember they are Mode C readings as well. Someone previously here cast doubt on the track displayed too. Whether that post still exists........? What explanation did your 'source' have for '353'?

There is a tendency to take what was displayed to the controller or brought up on a replay screen as 'the information from the aircraft'. It may have had significant massaging before it appears on the screen. For example ADS-B and SSR are always going to be out of step and your system is receiving both so to avoid the position report jumping back and forth the information from the aircraft SSR transponder and the ADS-B downlink are processed by a 'multi-sensor tracker' of some sort and converted into a 'Track' for the aircraft.

The reports state that the controllers were receiving ADS-B reports from the aircraft. If that is the case then they would be receiving those positions a lot more frequently than the Track update on the controller display. Each of the ADS-B reports gives detail on the GNSS position, the time the position was valid, the altitude of the aircraft, the vector state of the aircraft, etc etc, (See RTCA DO-260B). This information will have been stored in the ATC systems. At best there will be a half second trail of this information, that would allow a very detailed trajectory (track, airspeed, ground speed and altitude profile - possibly with GPS altitude as well) to be created relatively simply.

I do not understand why this has not been done it would not see the aircraft all the way to the surface but it would answer many questions and remove some of the wilder speculations.

[Superpilot]

EK409 - Flights list - Flightradar24

I believe there's a week cut off for historical flight track data provided by FR24 (The free version at least). In any case, they only record position by the looks of it every minute or two so would not be accurate enough.