Lionair plane down in Bali.
PJ re nothing of substance, see #790,
Re FDR Trace, around 07:09:05, split between air and ground speed then increase in airspeed.
VS previously steady at 600ft/min, deceases to 400 then increase to 900-1100ft/min, at the same time as oscillating pitch and roll, generally towards nose up, then nose down.
Comparing this with the previous incident one might deduce a rapid onset downdraught, even a micro burst windshear.
Re FDR Trace, around 07:09:05, split between air and ground speed then increase in airspeed.
VS previously steady at 600ft/min, deceases to 400 then increase to 900-1100ft/min, at the same time as oscillating pitch and roll, generally towards nose up, then nose down.
Comparing this with the previous incident one might deduce a rapid onset downdraught, even a micro burst windshear.
I understand this is only the preliminary report but I do hope that the final report will mention whether the crew was actually visual or not at the MDA. Many here are assuming that just because the PF mentioned runway not in sight at 900 ft, he was also not visual at the MDA. There is no mention of this in the report. They may have become visual between 900 ft and MDA but then lost it again below minimums due to heavy rain.
I do recall a similar incident in Bangkok around 1999 where a Qantas 744 lost visual reference with the runway just seconds before touch down. If I remember correctly, the F/O who was flying initiated a GA, but the captain cancelled it when the wheels actually touched the runway, resulting in an overrun.
Another matter of concern is why there is a 'handing over' of the controls from the PF to the PM at such a critical phase of flight? Did the captain simply took over control because the PF didn't initiate a go-around? Or is it Lion Air SOP that requires only the captain to perform go-arounds? Or did the F/O simply handballed the controls to the captain because he wasn't competent enough to handle the GA himself? I hope these questions will be addressed in the final report.
I do recall a similar incident in Bangkok around 1999 where a Qantas 744 lost visual reference with the runway just seconds before touch down. If I remember correctly, the F/O who was flying initiated a GA, but the captain cancelled it when the wheels actually touched the runway, resulting in an overrun.
Another matter of concern is why there is a 'handing over' of the controls from the PF to the PM at such a critical phase of flight? Did the captain simply took over control because the PF didn't initiate a go-around? Or is it Lion Air SOP that requires only the captain to perform go-arounds? Or did the F/O simply handballed the controls to the captain because he wasn't competent enough to handle the GA himself? I hope these questions will be addressed in the final report.
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Based on gossip here about F/Os in Lion and what they can and cannot do, I would suggest the Captain probably does the landing (.........and normally on the runway...)
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The first of three recommendations of the NTSC is an absolute ripper!!
Words to the effect of "....Pilots are reminded of the importance of carrying out a missed approach if visual reference is not obtained by the minima...."
Some wise old pilot once told me that there are only 2 golden rules in aviation Lowest safe's, and Minimas.
The first rule NEVER go below LSALT unless you are visual, (councils never give building approvals to build anything above LSALT's!!).
The second rule NEVER go below minima's unless you are visual, if you reach the minima and it is not "Bank of England Safe" go arround like a golf ball bouncing off concrete.
What a sad unnecessary waste of an aircraft. Absolute pure dumb luck everyone wasn't killed. It will be interesting to see what the Indonesian authorities do to clean up this mess.
Words to the effect of "....Pilots are reminded of the importance of carrying out a missed approach if visual reference is not obtained by the minima...."
Some wise old pilot once told me that there are only 2 golden rules in aviation Lowest safe's, and Minimas.
The first rule NEVER go below LSALT unless you are visual, (councils never give building approvals to build anything above LSALT's!!).
The second rule NEVER go below minima's unless you are visual, if you reach the minima and it is not "Bank of England Safe" go arround like a golf ball bouncing off concrete.
What a sad unnecessary waste of an aircraft. Absolute pure dumb luck everyone wasn't killed. It will be interesting to see what the Indonesian authorities do to clean up this mess.
VS previously steady at 600ft/min, deceases to 400 then increase to 900-1100ft/min, at the same time as oscillating pitch and roll, generally towards nose up, then nose down. Comparing this with the previous incident one might deduce a rapid onset downdraught, even a micro burst windshear.
Note the steepening curve in your own wind-shear example.
(The same for the onset of less stable flight in roll and such - face it, autopilots are often steadier than human hands.
)In a wind-shear event, I'd expect some germaine CVR comments (based on what usually is heard in such events) - along the lines of "WTF!!? POWER POWER! Pull the nose up!"
But a full second-by-second CVR transcript is exactly one of those elements missing from this prelim report.
Always remember that the scientific approach to an investigation is not to ask "What evidence here is consistent with wind-shear (or other theory)?" - but "What evidence here is absolutely inconsistent with anything except wind-shear?"
I do hope that the final report will mention whether the crew was actually visual or not at the MDA. Many here are assuming that just because the PF mentioned runway not in sight at 900 ft, he was also not visual at the MDA. There is no mention of this in the report.
Last edited by pattern_is_full; 15th May 2013 at 17:30.
safetypee;
Re, ". . . one might deduce a rapid onset downdraught, even a micro burst windshear."
Yes, possibly.
Some thoughts on the data made available and the possibility of windshear.
First, we don't have wind direction and speed parameters, engine thrust parameters or any of the autopilot controls, (heading selection, FPA-VS selection, airspeed selection).
We don't know if the non-precision approach was being flown using "selected" autopilot values for the airspeed and FPA (or VS), or if it was a "managed" (Airbus terms, I know), approach being flown automatically through the FMC.
Therefore we can't say for sure whether the variations which occur in pitch, FPA, VS, airspeed just prior to the autopilot disconnect are a result of such selections or a result of environmental factors.
The variations in airspeed, groundspeed, pitch, roll, VS / FPA prior to and even after AP disconnect, are relatively minor and well within an energy envelope that would counter windshear.
The autopilot was disengaged (as indicated by disengagement of VNAV / LNAV modes) at 07:09:23 just below 600ft RA.
At about 07:09:11, at 750ft RA, the pitch reduces from 1deg NU to 2deg ND. At the same time, the FPA shows a reduction from -1deg to - 5deg and the airspeed and groundspeed concurrently increase.
The difficulty with a windshear theory is, no attempt was made to increase pitch beyond 2deg NU to arrest what became a 1000fpm VS. We don't know if thrust was applied or not because the engine parameters have not been included in this report.
However, microburst or no, the immediate key in this CFIT accident is the captain's decision to continue the approach, a) after the F/O reported that he could not see the runway and, b) after the captain had taken over and he himself reported at 150ft that he could not see the runway.
A go-around from 20ft is usually successful providing one is aware of two things:
a) engines must be spooled for immediate response, and,
b) it is likely that from a low-energy, low-altitude go-around, the airplane will momentarily touchdown on the runway before continuing.
This certification requirement & qualification caters to CATII & III low-level go-arounds where momentum of the airplane will continue the descent for a few seconds. This is also the reason many countries have added 50' to any non-precision approach minima - to cater to a slight loss in altitude should a go-around decision be made; it keeps the aircraft (and the crew) from busting NPA minima.
Anyway, there's not sufficient information to do other than continue guessing what this crew was doing and why and what both the Lion Air, and the NTSC response may ultimately be.
Re, ". . . one might deduce a rapid onset downdraught, even a micro burst windshear."
Yes, possibly.
Some thoughts on the data made available and the possibility of windshear.
First, we don't have wind direction and speed parameters, engine thrust parameters or any of the autopilot controls, (heading selection, FPA-VS selection, airspeed selection).
We don't know if the non-precision approach was being flown using "selected" autopilot values for the airspeed and FPA (or VS), or if it was a "managed" (Airbus terms, I know), approach being flown automatically through the FMC.
Therefore we can't say for sure whether the variations which occur in pitch, FPA, VS, airspeed just prior to the autopilot disconnect are a result of such selections or a result of environmental factors.
The variations in airspeed, groundspeed, pitch, roll, VS / FPA prior to and even after AP disconnect, are relatively minor and well within an energy envelope that would counter windshear.
The autopilot was disengaged (as indicated by disengagement of VNAV / LNAV modes) at 07:09:23 just below 600ft RA.
At about 07:09:11, at 750ft RA, the pitch reduces from 1deg NU to 2deg ND. At the same time, the FPA shows a reduction from -1deg to - 5deg and the airspeed and groundspeed concurrently increase.
The difficulty with a windshear theory is, no attempt was made to increase pitch beyond 2deg NU to arrest what became a 1000fpm VS. We don't know if thrust was applied or not because the engine parameters have not been included in this report.
However, microburst or no, the immediate key in this CFIT accident is the captain's decision to continue the approach, a) after the F/O reported that he could not see the runway and, b) after the captain had taken over and he himself reported at 150ft that he could not see the runway.
A go-around from 20ft is usually successful providing one is aware of two things:
a) engines must be spooled for immediate response, and,
b) it is likely that from a low-energy, low-altitude go-around, the airplane will momentarily touchdown on the runway before continuing.
This certification requirement & qualification caters to CATII & III low-level go-arounds where momentum of the airplane will continue the descent for a few seconds. This is also the reason many countries have added 50' to any non-precision approach minima - to cater to a slight loss in altitude should a go-around decision be made; it keeps the aircraft (and the crew) from busting NPA minima.
Anyway, there's not sufficient information to do other than continue guessing what this crew was doing and why and what both the Lion Air, and the NTSC response may ultimately be.
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Apparently, the crew had the runway in sight at MDA and this would be on the CVR. If confirmed, the first recommendation might not be that justified.
Go around could have been decided earlier when the sink rate was higher than 1000 ft/mn and the approach likely to be destabilized.
Initiating a goaround on short final would have been a better idea from the copilot than giving the controls back to the captain.
It seems to me that the report wants to underline potential issues with the procedures when the problem might be somewhere else.
Go around could have been decided earlier when the sink rate was higher than 1000 ft/mn and the approach likely to be destabilized.
Initiating a goaround on short final would have been a better idea from the copilot than giving the controls back to the captain.
It seems to me that the report wants to underline potential issues with the procedures when the problem might be somewhere else.
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Not typed on a B737, but why was the auto throttle system disconnected at the same time as the AP at minimums? Can you not have the ATs working for you on the B737 with its AP off?
Last edited by Oakape; 15th May 2013 at 22:55.
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If they were at flaps 40,retracted to flaps at 15 at 20 feet when the speed may be below vref and a sluggish increase of thrust then...well..
Last edited by de facto; 16th May 2013 at 03:00.
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Therefore we can't say for sure whether the variations which occur in pitch, FPA, VS, airspeed just prior to the autopilot disconnect are a result of such selections or a result of environmental factors.
b) after the captain had taken over and he himself reported at 150ft that he could not see the runway.
Last edited by MountainBear; 16th May 2013 at 03:59.
1/ They either had the required visual reference ( in this case Runway threshold in sight ) at or about the minima then lost visual,
or 2/ they never saw the runway at all
Either way it Doesn't absolve them from the stupid act of flying a perfectly serviceable Jet into the water.......
If they were visual and landed in the water they are even more incompetent than words can describe.
The only, and I underline only excuse would be a Windshear or Microburst at or after the minima that they could not recover from........
or 2/ they never saw the runway at all
Either way it Doesn't absolve them from the stupid act of flying a perfectly serviceable Jet into the water.......
If they were visual and landed in the water they are even more incompetent than words can describe.
The only, and I underline only excuse would be a Windshear or Microburst at or after the minima that they could not recover from........
Last edited by nitpicker330; 16th May 2013 at 04:19.
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Anyway, there's not sufficient information to do other than continue guessing what this crew was doing and why and what both the Lion Air, and the NTSC response may ultimately be.
(1) The SIC (PF) notes that he cannot see the runway at 900'
(2) Sometime between 900' and MDA there is a window in the weather and at MDA he can see the runway.
(3) They get hit by a microbust and their VS increases by almost 1000 ft/min. However, this goes undetected for two reasons. 1) they are concentrating on keeping the runway in sight and 2) at this stage in the flight a micro burst would be deceiving because they are landing. It drives them in the direction they expect to go, down.
(4) The SIC loses sight of the runway again.
(5) The PIC senses something is wrong so he takes the manual controls. Now, the startle factor is in play. The plane is descending much faster than he is used to. Someone back in the thread stated that the PIC said that a big force was pushing him to the ground. If this comment is true that suggests he is feeling the high rate of descent from the microburst that is already over (and which has gone undetected.) The PIC now has some serious cognitive dissonance going on because he has two competing priorities 1) where is runway? and 2) why does the plane feels like it is falling too fast? By the time he resolves this test in his head and calls for a go around it is too late. It is worth pointing out that this delay in dealing with a startle effect is exactly the type of thing one would expect to see in a person suffering fatigue, especially cumulative fatigue.
The problem with this scenario is is that even the engine data might not be too helpful. It is only going to tell how the crew responded to events and not what caused those events. One might be able to tease out some data regarding how much of the descent in the flight path was a direct result of pilot command vs weather related. But they didn't miss the runway by much and one might run up against margin of error problems in the engineering data. In may be that the final report is no more illuminating than the preliminary report in this regard.
You do realize that the FDR records all data don't you?
IAS TAS HDG TRK GS W/V SAT TAT IRS position.......plus hundreds of other systems......
If there was a Windshear or Microburst THEY WILL KNOW.
The SIC never called Visual at the minma, the Captain never said anything at the minima.........
Does that tell you anything????
It tells me that the PIC flew the a/c below the minima without visual reference hoping the runway was in the right place ........at 20' be realized there wasn't a nice runway under him........tooooo late.
IAS TAS HDG TRK GS W/V SAT TAT IRS position.......plus hundreds of other systems......
If there was a Windshear or Microburst THEY WILL KNOW.
The SIC never called Visual at the minma, the Captain never said anything at the minima.........
Does that tell you anything????
It tells me that the PIC flew the a/c below the minima without visual reference hoping the runway was in the right place ........at 20' be realized there wasn't a nice runway under him........tooooo late.
Last edited by nitpicker330; 16th May 2013 at 05:19.
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It tells me that the PIC flew the a/c below the minima without visual reference hoping the runway was in the right place
Absent an actual statement from the crew, we do not know what they saw at MDA.
If there was a Windshear or Microburst THEY WILL KNOW.
Last edited by MountainBear; 16th May 2013 at 05:33.
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Mountainbear,
Your point 3) the vs didn't increase by 1000 fpm it increased to 1000fpm, anything greater than 1000fpm is by definition unstable and requires a go-around if below 500'.
1000 fpm on final is not completely unusual, but it is on the limit, but OK to continue. The 737 800 has enhanced EGWPS, with predictive windshear, both systems to avoid WS microbursts, the wind on the ground was 120/6, although there was a localized shower in the area. Nothing on the FDR indicates microburst. When you have been in a microburst it is not something that gives you some vague feeling of unease, you very quickly know that things are not right, bigtime. The Lionair management made a statement before the wreckage was cold that weather played no part in the disaster, that is a very unusual thing to do.
bottom line, if a missed approach had been carried out when visual reference was lost @ 150 (something that must have been anticipated by the F/O's statement at 900'), we would be making comments on another thread.
Your point 3) the vs didn't increase by 1000 fpm it increased to 1000fpm, anything greater than 1000fpm is by definition unstable and requires a go-around if below 500'.
1000 fpm on final is not completely unusual, but it is on the limit, but OK to continue. The 737 800 has enhanced EGWPS, with predictive windshear, both systems to avoid WS microbursts, the wind on the ground was 120/6, although there was a localized shower in the area. Nothing on the FDR indicates microburst. When you have been in a microburst it is not something that gives you some vague feeling of unease, you very quickly know that things are not right, bigtime. The Lionair management made a statement before the wreckage was cold that weather played no part in the disaster, that is a very unusual thing to do.
bottom line, if a missed approach had been carried out when visual reference was lost @ 150 (something that must have been anticipated by the F/O's statement at 900'), we would be making comments on another thread.
Mountainbear:-- I can't think of any other reason why they would fly into the sea!!!
In the absence of Windshear/Miroburst ( no evidence of such phenomena ) a competant crew wouldn't land in the water if visual and that leads me to say they must NOT have been visual. Or the Captain seriously needs glasses.
You can sugar coat it any way you like but them's the facts according to the NTSC.
In the absence of Windshear/Miroburst ( no evidence of such phenomena ) a competant crew wouldn't land in the water if visual and that leads me to say they must NOT have been visual. Or the Captain seriously needs glasses.
You can sugar coat it any way you like but them's the facts according to the NTSC.
Last edited by nitpicker330; 16th May 2013 at 07:47.
The notes say magnetic heading with the line above DME distance and the line below pitch angle. It looks like the FO / pilot flying flew the non precision approach as you would expect using the autopilot. At MDA with or without suitable visual reference (but the latter seems more probable) the autopilot reverted to control wheel steering and shortly afterwards he flew manually.
The FDR shows the approach to have become unstable with pitch, roll and speed deviations. I am unfamiliar with Lion procedures, but at this point using any sensible procedures one of the two pilots should have called for a go-around. Handing over control at low level and finally deciding to go-around at 20 feet is clearly dangerously poor practice and led directly to the accident.
For whatever reason the co-pilot seems to have been way behind the aircraft. He was obviouly uncomfortable at not seeing the runway at 900 feet. Going below the MDA without disconnecting the autopliot is a violation of Boeing procedure. With the aircraft reverting to control wheel steering he was forced to take control, which the FDR shows he did poorly. Poor weather, poor flying, poor adherence to, or design of procedures, and the holes in the swiss cheese are lining up. The only amazing thing is that through pure dumb luck the attempted go-around resulted in a reduction in sink rate allowing everyone to survive. All in all it is a sobering indictment of just how bad things have got.
The FDR shows the approach to have become unstable with pitch, roll and speed deviations. I am unfamiliar with Lion procedures, but at this point using any sensible procedures one of the two pilots should have called for a go-around. Handing over control at low level and finally deciding to go-around at 20 feet is clearly dangerously poor practice and led directly to the accident.
For whatever reason the co-pilot seems to have been way behind the aircraft. He was obviouly uncomfortable at not seeing the runway at 900 feet. Going below the MDA without disconnecting the autopliot is a violation of Boeing procedure. With the aircraft reverting to control wheel steering he was forced to take control, which the FDR shows he did poorly. Poor weather, poor flying, poor adherence to, or design of procedures, and the holes in the swiss cheese are lining up. The only amazing thing is that through pure dumb luck the attempted go-around resulted in a reduction in sink rate allowing everyone to survive. All in all it is a sobering indictment of just how bad things have got.
Last edited by lederhosen; 16th May 2013 at 08:25.
Agreed, the FO may have been a poor stick and rudder Pilot after the minima but the Captain wasn't incapacitated, so what was HE doing as PM?????? Obviously not much...
It doesn't matter who is flying, the Captain is still responsible for the safe conduct of the Aircraft at all times.
It doesn't matter who is flying, the Captain is still responsible for the safe conduct of the Aircraft at all times.