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-   -   Turkish airliner crashes at Schiphol (https://www.pprune.org/rumours-news/363645-turkish-airliner-crashes-schiphol.html)

chekib 2nd May 2009 13:30


Descending from above onto the glide slope is so common any competent crew can do it with no risk. It is a non event
May be y're right in, but no need to remind you that it may decrease safety margin specially at low alt GS interception, busy airport, and training flight.

chekib 2nd May 2009 13:35


Amazing, do Airbus manuals contain instructions on how to use toilet paper too?
:ok:
i flew the A320 and now the B737 NG, no need to begin comparing these two airplanes, but it is amazing to see that boeing is trying these last 5 years to change it's FCOM to be as similar as possible to airbus A320

CDRW 2nd May 2009 17:34

Bubbers - I was always taught that there was a risk of capturing a false G/S if capturing from above. Its was a fail to catch the slope from above.

Mu - great point on why Airbus drivers monitor the thrust levers - maybe it just feel right to have ones hands on the levers?

CHfour 2nd May 2009 18:35

Since we are going off topic and talking about capturing a glideslope from above, I'd just like to ask a quick question. Has anyone ever captured a false glideslope? I've captured from above numerous times but never been 100% high, which is what would be required to do it if I remember correctly. Also, I don't see how any normal jet airliner could maintain the glide on that profile.

Edit: Found this which makes a false GS capture even more unlikely.


False signals may be generated along the glide slope in multiples of the glide path angle, the first being approximately 6š degrees above horizontal. This false signal will be a reciprocal signal (i.e. the fly up and fly down commands will be reversed). The false signal at 9š will be oriented in the same manner as the true glide slope. There are no false signals below the actual slope. An aircraft flying according to the published approach procedure on a front course ILS should not encounter these false signals.

Huck 2nd May 2009 19:50


Has anyone ever captured a false glideslope?
Yep, in a King Aire, long ago. It started to capture, then clicked off the autopilot.....

Byrna 2nd May 2009 21:06

I am sorry to everyone if I came across as arrogant. That was certainly not my intent. I think I also forgot that I was posting in one of the professional pilot forums on PPRUNE and I probably should have posted my comments more in a forum like Spectators Balcony.

However, my main points about concentrating on flying the aircraft have been made by others in this thread also, albeit in more detail due to their professional knowledge of aviation. But instead of commenting on flight procedures, I would like to ask some questions which have bugging me for some time now:

(1) Knowing these facts and the warnings which were being generated in the cockpit, what would have been your priorities as a 737NG-type-rated pilot to bring the plane back under control after the first sign of "trouble" or after the first warnings started appearing (left altimeter, gear down warning etc...)?

(2) Are there ANY conditions which would have caused the throttles to go to IDLE BY DESIGN of the 737-800's autopilot systems (as opposed to a malfunction?)

Again, I am sorry for my tone, and I do realize that I over-stepped my bounds.

John

bubbers44 2nd May 2009 21:17

Landing at MIA from the east but landing on 09 we always captured the glide slope from above unless traffic required us to extend downwind leg. Nobody refused it because basic airmanship made it simple. I retired 5 years ago but I hope basic airmanship hasn't decreased to this level that a flight sim guy can do it. On the B767 I was the copilot doing initial operating experience and my check airman captain didn't arm the approach mode so flew through the gllide slope. He wanted to do that leg so he was confused so I told him to go to idle power, autothrottles off, speed brakes, vertical speed down and intercept from above. It was at the end of a long day and I didn't want to go around for no reason. He was embarassed and said I have been teaching in the sim too long. I didn't care because I was thirsty!

TWN PPL 3rd May 2009 02:55

1,400' V/S to capture the G/S at 1,330'.
Final flap set done at 990'. Engine not spooled up.
When did they complete the Before Landing Checklist?
Does Turkish Airline have a stabilized approach criteria?
If they were stable at 1,000' with check list done.
This would have been a nonevent / with 3 man crew
Stable at 1,000'
would have given them more time to be more observant and call out:
"SPEED" on the ASI
"IDLE" on the FMA
Or realized that the thrust lever was in the unusual position (index unit)

Centaurus 3rd May 2009 07:43


Has anyone ever captured a false glideslope
Manila circa 1985 in a 737. . Radar vectored high and discovered perfectly flyable glide slope of about 5-6 degrees. Picked the problem by comparing DME v Height. While descending at idle thrust at 8 miles out we were showing very slightly above this glide slope on the ILS. Reported it after landing and the Manila CAA did a flight test and confirmed the presence of this steep glide slope. Error in ground maintenance. A few months earlier an Air Manila (?) B707 crashed just short of the same runway while descending CAVOK. The captain swore he was on glide slope - which no doubt he was, except it was the flyable false one. Been like that for ages apparently and no aircraft had reported it. The 707 had descended with full flap and idle thrust with high rate of descent to remain on GS. Despite this the captain elected not to go-around as he said he thought the noise of the engines spooling up would likely frighten the passengers. Maybe he thought a crash landing would be less scary?

Avman 3rd May 2009 10:46

Just for the record Centaurus: It was a China Airlines B707 in 1980.

Rananim 3rd May 2009 15:26

Byrna,
They received two warnings:
i)EGPWS
ii)Stick-shaker

If a RA fails,an amber annunciation appears on the PFD.As it didnt fail,there was no warning.If the pilot connected the EGPWS warning to the RA erroneous reading,thats only half the battle.He must know the implications of the erroneous reading for his approach.For this he has the MEL(O) data (but the #1RA failure hasnt been officially tagged) so he now has to rely on his own systems knowledge.
There were 3 more cues,2 visual,1 tactile.
i)RETARD instead of MCP SPD in FMA(top left PFD)-missable
ii)Decaying speed on speedtape(fly the plane!this after all is the only cue you really need...)
iii)Thrust levers at idle stop(tactile IF the PF has his hands on the levers)

hetfield 3rd May 2009 15:33

This accident was simply due to poor airmanship.

Roger, over and out!

That's it!

Mods please feel free to close this thread.

busidriver 3rd May 2009 20:09

Hetfield:

My answer to your post:

_ _ _ _ _ _ _ _

Clue: I have two of them; they're big and hairy.

Seriously, as long as people like you, with your intellect, who jump on a few words in a preliminary report and draw such childish conclusions, are in the flight decks of airliners, human intelligence remains a weakness in the piloting fraternity.

busidriver 3rd May 2009 20:56

I say again:

A few words in a preliminary report...

But, please accept my apologies. I know I'm not Captain Perfect.

Maybe you are?

BigHitDH 3rd May 2009 22:58

The more I read this, the more ridiculous it becomes.

My humble opinion as a low hour PPL trainee.

The skills to avoid this are embedded within the first few hours of a PPL. Instrument scan, are we at the right speed? Stall awareness, recognize a low speed/high AoA condition, does the view out the window look right? Approach, hands on throttle and stick, fly the airplane. Who's flying this thing?

Something is seriously wrong if these basic items are missed. By 3 people.

lomapaseo 3rd May 2009 23:14


Something is seriously wrong if these basic items are missed. By 3 people.
we've heard this over and over ad nauseum for the last few hundred posts and it doesn't provide any closure on this accident cause while wasting a good deal of bandwidth in this thread.

give it a rest

The only thing that is worth while discussing are the methods available to mimimize missing of the basic items by the human. That has been discussed as well but is still open for positive contributions from knowledgeable folks

bubbers44 4th May 2009 00:01

Can anyone not fault this crew for not monitoring the throttles? Hopefully this will never happen again. Some statements here make me think it may. Watch what automation is doing to your aircraft and make sure it is doing what you want.. If it isn't, disconnect it.

TWN PPL 4th May 2009 03:48


The only thing that is worth while discussing are the methods available to mimimize missing of the basic items by the human. That has been discussed as well but is still open for positive contributions from knowledgeable folks
Yes, Boeing.
Approach to Stall Recovery in the non-normal Maneuvers Section QRH.


Can anyone not fault this crew for not monitoring the throttles?
Forget about all the bell and whistle during CRZ and DES.
Let's say at 500' stable for VMC
@460' stick shakers activated
Maximum thrust...
But damn, the thrust levers got them again... "it moved back to idle"
They try hard to save the airplane from there on.

bjornhall 4th May 2009 05:19


we've heard this over and over ad nauseum for the last few hundred posts and it doesn't provide any closure on this accident cause while wasting a good deal of bandwidth in this thread.

give it a rest

The only thing that is worth while discussing are the methods available to mimimize missing of the basic items by the human. That has been discussed as well but is still open for positive contributions from knowledgeable folks
I think you are treating incompetence as if it was a human error.

Of course we all know that humans are susceptible to errors, the best pilots can make the worst mistakes, the system is only made safe by trapping and mitigating such errors, not by relying on them never occuring, etc etc etc. I doubt anyone contributing here lack that understanding.

But not monitoring airspeed on final is too basic to fall under the "to err is human" heading. The system shall be pilot proof, not idiot proof. Sweeping every display of pilot error under the same "human error" blanket risks making one blind to an industry wide training problem, if such a problem exists.

Is there no difference between errors made because all humans make mistakes, and errors made because the pilot was not a sufficiently good pilot? Until 25 years ago, all errors were put in the second category; for the last 25 years, all errors have been put in the first category. Perhaps it is time we start recognizing that both type of errors are made, and the same types of solution will not solve both types of problem.

I think it is striking how many of the recent accidents that appear as if they could have been prevented by better and, most importantly, more training. Looking back 10, 15, 20 years, that was not the case; back then, you could almost always identify "system failures" in each accident, and find solutions in terms of technical and procedural improvements. Is it just me who see a change in that pattern?

Finn47 4th May 2009 06:32

Itīs a disappointment that the Dutch safety board did not include anything like a CVR transcript in their initial report. As I think I mentioned earlier, the last time they did a full scale investigation it took them almost 3 years to come up with a final report which included a transcript...


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