Tag Archives: Deborah Hersman

Losing Competence Part V: Asiana 214 and the Loss of Control Accidents

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document.write(" serif">Automation and Hubris

Bernard Ziegler designed the Airbus to be pilot-proof. He is a good pilot, and he noticed that many pilots are less skilled than himself. In the interest of safety, he designed an airplane that could not be stalled. But it has been known for thousands of years that hubris is followed by nemesis, that Pride goeth before destruction, and an haughty spirit before a fall. (Proverbs, 16:18)

Hubris is arrogance before the gods. The goddess Nemesis alone can see the fine line between doing the best work you can and believing that your work is somehow superior. Cross the line and she is ruthless, finding your fatal flaw and using it to bring you down.

AF 447 was the fall of the hero. Pilot carelessness led the airplane into a line of thunderstorms. Supercooled water drops overwhelmed the pitot heaters, temporarily removing all three sources of airspeed information. The autopilot dropped off. The flight control computers switched from Normal to Alternate Law. The airplane can be stalled in Alternate Law.

Human or robot, there is always a fatal flaw.

How can we work with imperfection?

Don't Bow Down

Mankind, when confronted with the complicated or the divine, tends to bow down in worship. This can be hazardous in aviation.

The new automation – glass cockpit, fly by wire, IRS and GPS – together bring a change at least as momentous as going from props to jets in the 1960's. The aircraft is now such a capable pilot on her own that she almost seems real. We called the Airbus Fifi. Rather than bowing down, we found it was much better to treat her like a person. Dare to know her and maintain a relationship.

In her early days, frustrated pilots would exclaim, “What the #$%* is it doing now?” On a go-around at KLGA the map display would disappear, the airplane sailing off the edge of the world because it had passed the last waypoint in the flight plan. Or on a miss from a visual approach at KMIA the power would suddenly go to idle. Finger trouble with the Autothrust. She was trying to maintain go-around speed.

But the answers are right in front of you on the FMA. (Flight Mode Annunciator, at the top of the Primary Flight Display) We began speaking for her, calling out any change in the FMA, so we all knew what she was doing, or thought she was doing.

And yes, most of the time she was a damn good pilot. Just as we are. Exactly the same, including the occasional lapse. Which is why there is more than one pilot aboard. And which is why the human pilot should never bow down and never step aside. Know her (the automation, Fifi, the airplane) as well as you can. Always monitor her as you would a human pilot and call out anything unusual. And if she's not doing what she is supposed to, take over. For those interested in pursuing the subject, there is an excellent video, Children of Magenta, of a lecture by an American Airlines training captain. The take-away is the same: if she's not doing what you want, take over and fly by hand. You don't have time to figure out what you did wrong with the automation.

Crew Concept – and Not Just Humans

Moving from props to jets, pilots were introduced to many new concepts: mach tuck, dutch roll, deep stall, etc. Perhaps the most important were the long, shallow drag curve and the slow spool-up time of the engines.

Moving into the fly-by-wire era, we have to accept that the airplane (her automation) is part of the crew. Philosophically, it is perhaps a stretch, but in the real world of the cockpit it is a game changer and a life saver. As soon as you accept that the airplane is part of the crew – not a superior or inferior, but an equal – everything starts to make sense. She sounds the cricket as the autopilot drops off. In Alternate Law she says Stall, Stall as the panicked pilot pulls back on the sidestick.

But if you're on approach below 1000 feet (critical phase of flight) and the descent rate is 1300 feet per minute and the airspeed is below Vapp then someone isn't doing what needs to be done. (Without a glideslope the airplane will not understand that something is wrong.) The software doesn't care if the airplane crashes. She is a good pilot but she has absolutely no self-preservation instinct, no will to live. Human pilots have, or they have no place on the flight deck.

Losing Competence Part III: Asiana 214 and the Loss of Control Accidents

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document.write(" serif">Today's News

NTSB Chairwoman Deborah Hersman continues to impress. Quoted today in the San Francisco Chronicle, she says: “What I'm telling you is that from 500 feet to 100 feet, there is no mention of speed.” That's on page A10. On page A12 there are two articles, Do pilots have adequate skills? by airline pilot James F. Atkinson, and When will FAA require alerts? by lawyer Robert A. Clifford. (I am not including links to these articles because you would have to be a Chronicle subscriber to read them.)

Atkinson rightly addresses basic flying skills and airmanship, pointing out that today's automated systems actually undermine skills. Clifford calls for mandatory low airspeed alerts, missing the point that this would make the pilots even dumber. (It is worth analyzing the terrific save by the captain of the Quantas A380 that had the uncontained engine failure. There was so much damage and so many (hundreds) of ECAM alerts that he finally said, Stop ECAM. Lets go backwards and just see what we've got left. That critical decision was the key to saving the airplane.)

Analysis of the Last Minute

At 1000 feet, 54 seconds before impact, someone says, Sink Rate. The throttles are at idle. The training captain tells the trainee, who is flying the airplane, to pull back. This is exactly the wrong thing to do. We will explore why that is so in greater detail in another post, but for now we'll say that they were at idle, on the back side of the drag curve, so total drag is increasing with angle of attack. As any pilot knows (see Stick and Rudder, 1944), instead of correcting the sink rate, pulling back on the control column actually increases the rate of descent and causes the speed to decay faster and faster.

At 200 feet, 18 seconds before impact, the training captain realizes they are too slow and moves to engage the autothrottle. After saying pull back he does nothing for 36 seconds while the airplane descends at over 1300 feet per minute. The target for any approach is 700 feet per minute. The engines are still at idle. They are well below approach speed.

Could they have done a missed approach that point? I will leave that for formal analysis, and point out only that these aircraft are designed to be able to do a baulked landing from any point before touchdown, but only if the engines are already spooled up and the speed is at approach speed, about 1.3 times the stall speed.

Ten seconds later, it was already game over. Perhaps the autothrottle had been armed, but most likely it had not actually been engaged, so thrust lever movement happened only now, at about 100 feet and 8 seconds before impact. And it will be another 5-7 seconds before the engines develop any useful power. So we see the slowest speed at 3 seconds before impact, at perhaps 40 feet above the water. This is where the passengers behind the wings see the plumes of water as the engines start to spool up. Meanwhile the stick shaker is going, indicating impending stall. Despite pulling back and belatedly adding power, they are still descending at 750 feet per minute, by my calculations. This is the first time anyone in the cockpit calls for a go-around. Of course it is too late. Way too late.

What the training captain should have done, back at 1000 feet and 54 seconds, is push the power up. Manually. With the thrust levers. The problem is that he would probably not been able to stabilize the approach from the idle thrust, slow (148 knots) and 1300 feet per minute sink rate descent. It would have been a neat parlor trick if he could have put on go-around thrust, pushed to counter the nose-up moment of the added thrust and bring the speed back up to bug (the approach speed), and then quickly brought the power back to approach power and held the speed. At 1000 feet he had room to fart around a bit, at least in theory. But airline Standard Operating Procedures (SOP's), his own airline's included, say that the approach must be stabilized by 1000 feet and remain stabilized, or else a go-around shall be performed.

So what the training captain really should have done is to say:

I have control.

Go-Around.

That's it. That's the last time the training captain, the Pilot in Command, had any say in the matter. That's when the pilots, the crew, gave up having any influence over the outcome.

It is sad, but true. It must be said. The pilots were incompetent.

Next: aerodynamics they should have understood . . .

Losing Competence Part II: Asiana 214 and the Loss of Control Accidents

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document.write(" serif">News and Public Relations

Deborah Hersman, The NTSB's Chairwoman, has taken some flak in the last few days. But from my perspective, she is one of the few in responsible positions who are looking good.

First a minor annoyance: on Saturday and Sunday news outlets kept repeating a young witness's observation that Asiana 214 came in “low and fast.” Many immediately available facts, including where the aircraft came to rest, made it a slam dunk that the aircraft was, instead, flying way too slowly.

Then on Monday the Korean Government announced they would be “inspecting all Korean B-777's”. On Tuesday and Wednesday various pilot unions called for Ms. Hersman's head, saying presumptions of pilot error were speculative and premature.

Please. I am used to the power players grandstanding their interests, but this is amateur hour. There is only so much ignorance out there.

The Last Thirty Seconds

Now let's get back to what we know. The cockpit cleared the breakwater nicely. The main landing gear and the tail did not. The speed at impact was 106 knots, within a knot or two of the stall speed. (The approach speed should have been 137 kt.) One and a half seconds before impact, engine power increased. Passengers in seats just behind the wing could see spumes of water being thrown up. At four seconds before impact the stick shaker operated, signifying an impending stall. At seven seconds someone is heard on the voice recorder calling for an increase in speed. In his interview the training captain said he went to push the throttles forward but the trainee already had. (Notice at least 5 1/2 seconds elapse between advancing the throttles and the increase in power. Seven seconds spool-up from idle is typical for a fanjet engine.) At 500 feet altitude the training captain became aware that they were too low (the PAPI lights were red over red) and he asks the trainee to pull back. The training captain also notices they are not aligned with the runway. Ms. Hersman says at that point they knew they were low and they were making lateral corrections to line up on the centerline of the runway.

These are the bare facts.

Flight Preparation in Seoul

Now let's go back twelve hours or so to the pilots' briefing. The dispatcher has already produced the flight plan with its route as close as possible to the minimum time track. The weather is good over the Pacific and at destination. Most likely they have fuel for a close alternate, such as Sacramento. It looks easy. But somewhere in the data available to the dispatcher and pilots are these two lines:

ISFO 06/005 SFO NAV ILS RWY 28L GP OTS WEF 1306011400-1308222359

ISFO 06/004 SFO NAV ILS RWY 28R GP OTS WEF 1306011400-1308222359

San Francisco airport (KSFO) always lands on runways 28L and 28R unless a winter storm blows through. With today's light winds and good visibility it is a near certainty that these runways will be in use. But decoding the two lines above (they are called NOTAMS, for Notices To AirMen) we find that the GlidePath (GP) is OuT of Service (OTS) for both runways. The When in EFfect (WEF) is from June 1, 2013 to August 22, 2013 at midnight. This is important because the aircraft cannot fly these approaches on autopilot in the way the pilots are used to.

Here is where we have to move into sensitive territory. (There will be more of these before we're done.) At the end of the article Terror on Jet, in The New York Times on Monday, July 8, we find these lines:

Some experts said that pilots often have little opportunity to practice landings without the aid of such technology . . .

Still, given that the weather was ideal and the guide lights (PAPI, or Precision Approach Path Indicator) were on, making a visual landing should not have been difficult for most commercial pilots . . .

on a difficulty scale of 1 to 10, this was a 2 or 3 at the most . . .

Pilot Judgment

A pilot's most important skill is his judgment. (see my Developing Pilot Judgment) He must look at the tasks and maneuvers ahead and ask two questions: Can the airplane do it? and Can I do it?

The former is mostly hard data in the Aircraft Flight Manual Limitations section, but it is also practical knowledge of what the aircraft's systems can and can't do and an understanding of the feedback systems that tell the pilot if the job is being done. (A good example is the AutoThrottle).

The latter question is the more important of the two: Can I do it? The only way to answer is through experience, and it is not measured in flight hours.

Training: have I been trained in this maneuver?

Practice: have I practiced it on my own? What were the results?

Recency: have I done one in the last 30 days? 90 days?

When Asiana's pilots were preparing for the flight in Seoul, the two NOTAM lines about the glidepaths on 28L and 28R should have triggered a dialogue:

“We're going to have to do an everything-off visual approach in KSFO. Has any of us been trained for this? Who has practiced one in the last year? Which of us has done one in the last 30 days? 90 days?”

I'd be willing to bet (I'll back this up in future installments) that none of the four pilots had flown a visual approach in the last 90 days. In that case, pilots with sound judgment would never have attempted the visual approach to 28L in KSFO. They would have diverted to Sacramento where there were long runways with functioning ILS systems.

Next: what else they did wrong . . .