NTSB update on Asiana 214

[TriStar_drvr]

I believe that those early 727 accidents came from mistakes made by pilots transitioning from props to jets. The engines took a while to spool up from idle, and the landing flaps added a tremendous amount of drag. If you didn't anticipate the spool up time the airplane could get slow in short order. Also, I don't think the stabilized approach concept was universally accepted then.

[aterpster]

I believe that those early 727 accidents came from mistakes made by pilots transitioning from props to jets. The engines took a while to spool up from idle, and the landing flaps added a tremendous amount of drag. If you didn't anticipate the spool up time the airplane could get slow in short order. Also, I don't think the stabilized approach concept was universally accepted then.

After the UAL SLC crash (a merged Capitol Airlines pilot) Flaps 40 for landing was made optional, with Flaps 30 preferred.

My company (TWA) blocked out Flaps 40.

The 727 was quite stable on approach provided you knew how to fly a jet.

[barit1]

To add to tdracer's list, American Airlines Flight 383 - Wikipedia, the free encyclopedia occurred within a few days of the SLC accident. No, it wasn't "low and slow", but merely awful damn low: 225 feet below the runway of the hilltop airfield.

Drum-type altimeter was cited as a possible contributor. (Wasn't this also cited in an early L-188 accident at LGA?)

[Capn Bloggs]

Yep, we need to get rid of those glass cockpit speedtape deathtraps and return to round dials

What a ridiculous conclusion. As already pointed out, the 727 was the transition from props to jets. Second, all those lessons/skills learnt over decades flying round-dial 727s, 737s, 747s and myriad other round-dial jets carried the industry through the glass age. Now that, at last, those flying skills are being lost, so the crashes are now increasing. Lack of flying skill combined with non-optimal ASI.

OK465, yet another sweeping generalisation. Nobody here is suggesting we return to the three-pointer altimeter. We're talking about airspeed.

[FGD135]

tdracer, I would echo what TriStar_drvr and aterpster said about the likely reason for those 727 EIS crashes, which means that they were nothing like the 4 stall crashes we have had since 2009.


My point is that for the recent crashes, there was a period of airspeed decay, of which the pilots were unaware. This airspeed decay allowed the aircraft to stall, and it was this stall that was the primary reason for the crash. Oh, and the pilots were trying to fly the plane - they weren't gazing out the window.


I am of the belief that this tendency to be unaware of the airspeed decay is a recent development, and that the presentation of airspeed via the "tape" (as opposed to the big round dial of yesteryear) has got a lot to do with it.


If it can be shown that the industry did not experience similar accidents in the period prior to the glass cockpits than this would tend to support my assertion, hence my interest in this period. I thank those on this thread that are assisting me identify similar accidents from that period.


So far, only one has been identified that has the prerequisite period of airspeed decay, of which the pilots appear to have been unaware. This was identified by ironbutt57 and I thank him for that.


That accident was in 1972. It was a 737-200 that had levelled at the MDA, with speed brakes extended. It had just been instructed to go around, and that instruction was acknowledged. The stickshaker had been operating for a good 20 seconds, but the airspeed did not decay all the way to the stall, so it is possible the PF was aware of the airspeed. It was the retraction of the flap to 15 degrees that brought on the stall. The full report here:


http://libraryonline.erau.edu/online...s/AAR73-16.pdf

[FGD135]

Now that, at last, those flying skills are being lost, so the crashes are now increasing.

Excellent point, Capn Bloggs, and that increasing accident rate is evident in that Airbus safety summary linked to by Oggi, a few posts ago.

[tdracer]

Now that, at last, those flying skills are being lost, so the crashes are now increasing.

Excellent point, Capn Bloggs, and that increasing accident rate is evident in that Airbus safety summary linked to by Oggi, a few posts ago.

If that's the conclusion you reached from the Airbus report, I must question your reading comprehension.


"Number of fatal accidents per year statistically decreasing since the 1960s despite rapidly increasing number of flights."
Lets take some numbers from that Airbus Report:
Number of fatal accidents/year:

2000: 10
2001: 9
2002: 8
2003: 7
2004: 4
2005: 9
2006: 7
2007: 8
2008: 8
2009: 8
2010: 8
2011: 5
2012: 4
2013: 6

So, 2013 had the 4th lowest number of fatal crashes in the last 20 years, 2011 had the 3rd lowest, and 2012 tied (with 2004) for the lowest - despite a 40% increase in the number of flights over that time period. Further, every generation of aircraft has had a better accident rate that the preceding generation.


I'm with olesak - now you're just making up.


BTW, even if you can't be bothered to read that number in the box, just exactly how much brain power does it take to recognize that the pointer on the speed tape and the barber pole are rapidly approaching each other? The PFD on the 777 is nearly twice the size of that on the 767 (64 sq. in. vs. 36 sq. in.) yet so far no ones stuffed a 767 because they couldn't read the airspeed. Asian didn't recognize that their airspeed was decaying dangerously BECAUSE THEY DIDN'T LOOK

[FGD135]

If that's the conclusion you reached from the Airbus report, I must question your reading comprehension.

tdracer, a picture tells a thousand words.


Have a look at the graph on page 9. That is the "10 year moving average accident rate per million flights". Look at the yellow line, representing 4th generation jet airliner types. You can see that line has been gradually increasing from its lowest point in 2005. Ditto the graph on page 10.

And, all the LOC-I graphs show an increase from 2005 (albeit with a slight decrease in recent years).

[Spooky 2]

The UAL 727 did not land short of the runway. If you can't get your facts right please go post on something like airliners.net where they believe all the BS that's posted

[Capn Bloggs]

Originally Posted by OK465

you guys have a perverted interest in airspeed being taken care of by something other than the pilot.

Err, no, merely an interest in presenting said airspeed info in a nice clear easy-to-interpret form.

I would quite happily disconnect the ATS and do it myself most times... if they'd let me!

Let's face it, as has been said before, the only reason they went to tapes was coz they couldn't fit a round dial in, because pilots didn't need to fly the nice new shiny glass machines, just use the autos... oh how wrong have they been proved.

[tdracer]

The UAL 727 did not land short of the runway. If you can't get your facts right please go post on something like airliners.net where they believe all the BS that's posted

Spooky:
Fatal Plane Crashes and Significant Events for the Boeing 727
United Airlines Flight 227 - Wikipedia, the free encyclopedia


Would you care to elaborate on what facts I posted that were incorrect?


I'm OK with spirited debate - the other stuff you can go

[FGD135]

tdracer,


That 727 accident was not the result of a stall. I suspect that most of the others on that list were also not stall related. I've lost count of how many times I've asked for stall related accidents.


Are you having trouble comprehending what I have asked for?

[porterhouse]

I've lost count of how many times I've asked for stall related accidents.

What the ...? No one here has better things to do than spend a day (or more) sifting through accident reports (many of them in 'legacy' format that are not easily searchable) and provide you with a number. And then it would be a wasted effort anyhow because as other remarked you have no clue about statistics, you simply shoot from the hip and think it will stick.

[tdracer]

That 727 accident was not the result of a stall. I suspect that most of the others on that list were also not stall related. I've lost count of how many times I've asked for stall related accidents.


Are you having trouble comprehending what I have asked for?

Perhaps I am. Asiana didn't stall, at least not in the conventional sense. Asiana crashed because the airspeed dropped dangerously low before the aircrew attempted corrective action. The 727 crashed because the airspeed dropped dangerously low before the crew attempted corrective action. Perhaps I'm being simplistic, but sounds the same to me

Setting aside the inconvenient fact that the original glass cockpit aircraft - 757/767 and A310, have never had a stall caused crash that wasn't due to bad air data (which you've chosen to ignore), explain this:
The Airbus report (which, BTW, mirrors similar reports from Boeing) says that Gen 1 aircraft (round dials) never got below 2/million fatal crashes. Gen 2 aircraft (round dials) did better, but never got below ~0.7/million fatal crashes. Gen 3 (glass), once the numbers became statistically significant, never got ABOVE 0.5/million (and are currently running ~ 0.2/million), while Gen 4 (glass plus) again once the numbers became statistically significant, has never been above 0.2/million and currently has, aghast! increased over the last few years from ~0.05 to ~0.10.


Oh the humanities!!!!


So, again, what is your justification for saying the accident rate is getting worse?

[FGD135]

Bring back the big round dial of yesteryear

... the original glass cockpit aircraft - 757/767 and A310, have never had a stall caused crash that wasn't due to bad air data (which you've chosen to ignore) ...

Those aircraft all had the big round dial of yesteryear! Careful now, you're supporting my hypothesis!

explain this ...

Explain what, exactly? With one exception, all of those trends are perfectly understood and accepted. (The exception is the gradual rise in the accident rate of 4th generation types since 2005).


You seem to think that I am saying the round dial airliners are safer than the glass cockpit types. That is NOT what I have been saying at all. Not even close. Go back and have a look at what I have been suggesting. Hint: airspeed "tape" vs airspeed as a big round dial.

[Jwscud]

It is worth pointing out that you are not necessarily actually reading numbers when you look at an airspeed tape. You will have the facility to input at least one reference bug and also a movable (usually magenta) speed bug. Surely when you scan the speed it is the position of the speed line relative to the bug and the trend if visible that you are looking at and not necessarily the digits themselves?

[RAT 5]

Surely when you scan the speed it is the position of the speed line relative to the bug and the trend if visible that you are looking at and not necessarily the digits themselves?

Absolutely spot on; and is true of all the magenta bug displays. Is the a/c white performance speed/hdg/alt lined up with the magenta cmd bug? Quick & easy to ascertain at a glance. In B732 I had to fly 210, 190, 170, 150kts etc for the various flap settings. Now on NG I just fly the green F bug which is high;lighted by the CMD bug. Simple easy. Am I + or - not a specific number.

[LiveryMan]

Seems to me this whole speed tape vs round dial argument is on the same vein as the old "3 vs 2 cockpit crew" argument, "metal skin vs fabric skin", "stagecoach vs railway" or "horse vs walking."

There are people who get to used to a certain way of doing things and are staunchly anti-change.

Not all change is for the better. But the in this case, I cannot see the benefits of old analogue gauges over modern MFDs.

[RetiredF4]

RAT 5
Absolutely spot on; and is true of all the magenta bug displays. Is the a/c white performance speed/hdg/alt lined up with the magenta cmd bug? Quick & easy to ascertain at a glance. In B732 I had to fly 210, 190, 170, 150kts etc for the various flap settings. Now on NG I just fly the green F bug which is high;lighted by the CMD bug. Simple easy. Am I + or - not a specific number.

Simple and easy, that is, but........
it is also a good example, how disconnected you might get. Not the numbers to be flown are remembered, but the correct composition of the display bug to bug to color to whatever. Developing trends like getting fast or slow are clouded by the perfekt working system, the autothrottle takes care of it. Actually there is no need to check it at all, as everything is fine day in and day out. You still remember the speeds it should show with different configurations? The thinking process has been replaced by limitless faith into the technical solutions implemented in those modern cockpits. That was the trap the Asiana crew ended up at last.

I sometimes wonder, why there are still switches, dials and other manual operated input devices available. Evverything goes to some input box first, before it is transfered to respective aircraft systems. When will the time come where you talk to the machine instead of making archaic manual inputs?

Back to the speed indication. There are several digital informations displayed in some analoge display form like some pressure gauges, the reason is? If the speed information would be considered as a vital information, or lets say if the autothrottle system would not jet have been invented and speeds would need to be manipulated manually, we would imho see normal analogue looking (but digital working) speed displays.

Then comes the day when the system is mishandled (Asiana) or goes on leave (AF447) to name two examples and nobody is able to mind the speed store anymore. To compare accident rates of different years and models is for no use at all, as the difference between a 1. generation 737 and a 737NG is not restricted to a different airspeed display. There are tons of other improvements leading to those low accident rates.

On the other hand the airspeed display of todays modern jets is not unsafe in itself, if training and proficiency reflect the inherent importance of monitoring the speed and enforce the knowledge, how those handles (stick and throttle) influence speed trends. But this speed display has been degraded from one of the few main instruments in the center of the crosscheck to a tiny speck of digital numbers on the edge of a display. What should we then expect from training?

[barit1]

That 727 accident was not the result of a stall.

Of course not. The aeroplane got to the crash site just before it stalled.

Put another way, trees and cows got too big.