For the aviation fans

[SwissVan]

Another tragic airliner loss

50 passengers and 12 crew lost

Aircraft was a 1994 Boeing 737-500

 

Looking at the FR track, it was over very quickly...descending 10'900 feet in less than a minute

 

How many times have we picked up people at the airport....It must be terrible for the friends and relatives waiting to see their friends / family at the destination to hear the announcement

 

 

 

 

ASN Aircraft accident Boeing 737-524 (WL) PK-CLC Jakarta-Soekarno-Hatta International Airport (CGK) (aviation-safety.net)

 

 

 

 

PK-CLC - Boeing 737-524 [27323] - Flightradar24

 

 

 

 

[Antoni]

Another tragic airliner loss

50 passengers and 12 crew lost

Aircraft was a 1994 Boeing 737-500

 

Looking at the FR track, it was over very quickly...descending 10'900 feet in less than a minute

 

How many times have we picked up people at the airport....It must be terrible for the friends and relatives waiting to see their friends / family at the destination to hear the announcement

 

 

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ASN Aircraft accident Boeing 737-524 (WL) PK-CLC Jakarta-Soekarno-Hatta International Airport (CGK) (aviation-safety.net)

 

 

indo.JPG

 

 

PK-CLC - Boeing 737-524 [27323] - Flightradar24

Sho, that is real sad.

 

What could have caused the sudden drop in speed round about the same time the sharp decent started?

[Bonus]

As you say Swiss, waiting at an airport to meet family and this happens must be unimaginable.

[SwissVan]

Sho, that is real sad.

What could have caused the sudden drop in speed round about the same time the sharp decent started?

No idea, I tried to look at the playback again but the link did not work.

Logic suggests a power reduction for whatever reason, but it would just be wild speculation, i would be cautious with FR data.

 

Hopefully the data recorders can be found intact.

[SwissVan]

Seems like the FDR and CVR locater beacon signals have been picked up

 

“On Jan 10th 2021 Rescue and Recovery Services found additional body and wreckage parts, amongst them a part of about 1 meter/3 feet length. Signals believed to originate from the pingers of the black boxes were located at two locations, these signals are going to be further investigated”

 

https://avherald.com/h?article=4e18553c&opt=0

[Spokey]

That is a tremendously high rate of descent. Apparently the aeroplane was intact as it impacted. The nose must have been crazy low like beyond 60 degrees ( my thoughts) just thoughts....scary.

Even just 8000 to 10000 ft per min down in an emergency descent the body angle is nowhere near what it must be for a reported 29000 ft per minute. A little surprised not to have bits flying off, but lets see what the boxes reveal.

[SwissVan]

That is a tremendously high rate of descent. Apparently the aeroplane was intact as it impacted. The nose must have been crazy low like beyond 60 degrees ( my thoughts) just thoughts....scary.

Even just 8000 to 10000 ft per min down in an emergency descent the body angle is nowhere near what it must be for a reported 29000 ft per minute. A little surprised not to have bits flying off, but lets see what the boxes reveal.

 

Do you think it would be possible for such a steep angle without human input? 

Meaning:

• Aircraft (AP or trim or...) malfunction  or 
• if one of the pilots initiated it on purpose

[kosmonooit]

Stalled (in bad weather) and fell out the sky? like that AF Airbus?

[SwissVan]

Stalled (in bad weather) and fell out the sky? like that AF Airbus?

 

If i recall the AF Airbus did not go down that quickly, it hit the water flattish

 

IMO the time for SJ182 from 10'900 ft to impact was to quick for a stall 

 

Anyway, seems like they are confident to find the data recorders tomorrow daylight when the search resumes, hopefully the questions can be answered quickly

[kosmonooit]

Depends what type of spin the aircraft gets into after the stall. A flat spin it will spiral down, wings flat & horizontal, the other type of spin is more full on nose down and faster decent (if memory serves)  current pilots here might confer or correct.

[Spokey]

I am trying hard to imagine what would cause that huge rate of descent. The Ground speed as shown would not indicate a straight nose down. I honestly think if the machine bunted over and pointed at the ground your 29000 ft per minute I would expect a good 600 kts or so.

Even a stall and departure from normal fight at around 10 000 feet should be fully recoverable........unless the aeroplane was completely unflyable for whatever reason.

It boggles my mind that it came down from 10000 feet in just 20 seconds. Massive decompression should have no cause for such loss of control from just 10000 feet unless controls were badly damaged. I had suspected an in flight break up in bad weather but again it has been reported as hitting the water intact.

Tonight I am having dinner with an ex Emirates Training Captain. Will discuss and see what he comes up with. The boxes will reveal a lot.

I am erring to the thought of flight control problems, sounds obvious I guess. Remember the Air Alaska MD83 crash in 2000. Stab trim Jack scew failed and the machine plunged into the Pacific. Even with that failure it never achieved even half of this 737’s Rate of Descent.

[Long Wheel Base]

This is the last thing the aviation industry needed right now after the last year.

RIP to the unfortunate souls onboard and condolences to the family and friends. Any aviation incident hits home hard to all us in the industry as well as those who are lovers of aviation.

[Spokey]

Depends what type of spin the aircraft gets into after the stall. A flat spin it will spiral down, wings flat & horizontal, the other type of spin is more full on nose down and faster decent (if memory serves)  current pilots here might confer or correct.

A normal spin typically results in the inside wing being stalled. The descent path is effectively around a vertical axis with a relatively shallow descent rate. Unloading the stall and use of rudder results in an easy recovery. I dont think they train these on PPL anymore. Flat spin is as you say, wings flat and nose possibly even above the horizon. For ease of description the aeroplane rotates flat more or less about its vertical axis while descending. Mostly irrecoverable unless in a purposefully designed aerobatics aeroplane. I believe that the descent rate is normally below 10000 feet per min (still high) but the rotation of the spin can be as much as 400 degrees per second.

 

The spiral is when both wings are flying and the aeroplane descends in a corkscrew flight path with an increasing speed and high rate of descent. Thing is the controls all still work and the situation is recoverable. Sad thing is many people just haul back on the elevator which just tightens up the spiral. Increased speed on the outer wing also tightens it up. It can run away very quickly if attention is not paid. Very easy to enter a high speed stall if aggressive on the recovery.

In the sim when we do the extreme unusual attitude recovery it can be quite disturbing having bells and aural warnings and flashing lights competing for attention while attempting the recovery.

[Spokey]

Do you think it would be possible for such a steep angle without human input? 

Meaning:

 

• Aircraft (AP or trim or...) malfunction  or 
• if one of the pilots initiated it on purpose

I dont fly 737’s and this is an older one. So much to think about. I would have thought stall for the drop in speed, but surely not a plunge to the ocean. If you read about Air Alaska MD83 the pilots required a high back pressure to recover from a stuck stab trim. 140lbs of pressure. Then the jack screw failed with the sustained hi loads and pushed the aeroplane nose down. Irrecoverable. But even then as I wrote earlier, still less than half this 737s RoD.

I hope that they can release some CVR or FDR info sooner rather than later. I would hate to suggest deliberate pilot action.

[Lotus]

A normal spin typically results in the inside wing being stalled. The descent path is effectively around a vertical axis with a relatively shallow descent rate. Unloading the stall and use of rudder results in an easy recovery. I dont think they train these on PPL anymore. Flat spin is as you say, wings flat and nose possibly even above the horizon. For ease of description the aeroplane rotates flat more or less about its vertical axis while descending. Mostly irrecoverable unless in a purposefully designed aerobatics aeroplane. I believe that the descent rate is normally below 10000 feet per min (still high) but the rotation of the spin can be as much as 400 degrees per second.

 

The spiral is when both wings are flying and the aeroplane descends in a corkscrew flight path with an increasing speed and high rate of descent. Thing is the controls all still work and the situation is recoverable. Sad thing is many people just haul back on the elevator which just tightens up the spiral. Increased speed on the outer wing also tightens it up. It can run away very quickly if attention is not paid. Very easy to enter a high speed stall if aggressive on the recovery.

In the sim when we do the extreme unusual attitude recovery it can be quite disturbing having bells and aural warnings and flashing lights competing for attention while attempting the recovery.

And this is why pilots earn the big bucks. When the **** hits the (turbo)fan.

[kosmonooit]

A normal spin typically results in the inside wing being stalled. The descent path is effectively around a vertical axis with a relatively shallow descent rate. Unloading the stall and use of rudder results in an easy recovery. I dont think they train these on PPL anymore.

 

..

 

No they don't train PPL on spins anymore anywhere as far as I know. but I had the privilege of  a good few back in the day. As terrifying as it was, I enjoyed the challenge (and the adrenaline). Thanks for the refresh of info on stalls, its been a while.

 

If I remember correctly, to recover from a spin : Rudder to opposite side of rotation, once rotation stops start pulling back to get out the dive. Live to tell the tale.

 

This is one of the things I used to use FS Sim for, for practicing procedures (one of the first versions that ran on DOS, still on my self here) I am sure they haven't coded it out of the latest versions, Simmers should give it a try.

 

How to initiate a spin? Straight and level flight, cut power, keep pulling back on yoke gently to maintain altitude, the speed will bleed off and the stall will start with a shuddering of the wings, then give the rudder a kick to one side and see what happens.  Some aircraft will be more spin resistant that others, so take the old training fav a Cessna 152