Current time: 01-20-2018, 11:08 PM Hello There, Guest! (LoginRegister)
Thread Rating:
  • 1 Votes - 5 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Dangers of AUTOPILOT
07-24-2013, 02:13 PM (This post was last modified: 07-24-2013 02:17 PM by throttlejockey.)
Post: #1
The perils of autopilot

[Image: plane.png?w=620]

Asiana Airline Flight 214, a Boeing 777 with 307 souls aboard, crashed on approach to San Francisco International Airport on Saturday, July 6th. The aircraft broke up and caught fire short of the button of Runway 28L. 123 of the passengers and crew staggered away without requiring hospital treatment, but 181 people were injured, 13 critically, and three passengers lost their lives.

It was a nasty landing accident on a nice summer morning. All reports noted that weather wasn’t a factor. It was what pilots call CAVOK, light wind, ceiling and visibility unlimited. It seemed to me, though, that the weather being ideal for flying didn’t necessarily preclude it from being a factor in the accident.

During the next few days, the National Transportation Safety Board (NSTB) recovered the aircraft’s flight data and cockpit voice recorders, analyzed them, then proceeded to do something unusual. At early press briefings, accident investigators tend not to reveal what they know or really suspect. The idea is to discourage “speculation.” (It never does, by the way; it only makes speculation more idle.) Breaking with this tradition, the NSTB’s new head, Deborah Hersman, stopped obfuscating, and shared the salient points with the world media as she received them.

The NSTB’s preliminary thinking reinforced my impression that weather was a big factor in the crash of Flight 214. In bad weather, it wouldn’t have happened. Flying in instrument meteorological conditions, the pilots wouldn’t ask for, or receive, clearance for a visual approach. Instead of hand-flying, they would program the computers to fly one of the standard terminal arrival routes in the murk. The human pilots on the flight deck would act as systems managers, monitoring the multifaceted autopilot that, “in conversation” with the navigational computers, manipulated the controls. They would land on a runway where the instrument landing system was operational (on Runway 28L the glideslope was being serviced), with a human pilot taking control – maybe – for the last 800 feet before touching down, engaging reverse thrust, taxiing to the terminal and Bob’s your uncle.

I wrote a column saying so, underlining that it was speculation of the kind that would probably dismay the Air Line Pilots Association International. (The powerful pilots’ union was furious with the NTSB for being so loose lipped with the press.) I expected to get letters asking how I could sink low enough to succumb to speculation and I wasn’t disappointed. What I did not expect, but was pleased to find in my mailbox, were letters from training-pilots writing in agreement with my speculation.

From Surrey, British Columbia, came this note: “I retired as a B767 captain about five years ago. I think your observations are spot on. In fact I am willing to wager a beer that that is what will be found to be the cause of this crash.”

When we presented situations which involved visual (no electronic) aids, it created shock and fear among all the pilots of both airlines…

Two of the pilots who wrote me worked for the subsidiaries of aircraft manufacturers contracted by foreign airlines to train their pilots in the operation of the equipment they purchased. “We expat instructors were forced upon them after the amount of fatal accidents … began to be noticed by the outside world,” wrote a pilot-instructor whose sojourn in Asia lasted from 2003 to 2008. “I am not kidding when I tell you that requiring them [Korean pilots] to shoot a visual approach struck fear in their hearts … with good reason.”

“Reading your article took me back more than a decade and I heartily agree with your assessment of the weather influence,” wrote a former Director of Flight Training and Standards for a major Canadian carrier, who spent years setting up training programs for both Asiana and Korean Air. “When we presented situations which involved visual (no electronic) aids, it created shock and fear among all the pilots of both airlines…”

Another training-captain thought the dilemma wasn’t just Asian. “This is a worldwide problem involving automation and the auto-flight concept,” he wrote. A first officer calling for the autopilot to be engaged 250 feet after takeoff is standard operating practice at some airlines. “How much actual flight time is that? Hardly one minute.”

This way we may have a 10,000-hour pilot in the left seat, another correspondent writes, with maybe 100 hours of actual flying time. We have taught our machines to perform so well that we forgot how to perform ourselves.

This is only speculation, but so it may have happened that the qualified crew of a major carrier, flying a serviceable aircraft in perfect weather over the flat surface of the ocean, without any known distractions from conflicting traffic, equipment malfunction, or anything else, while hand-flying in visual meteorological conditions allowed the approach to become unstable and made no attempt to go around until seconds before impact.

User-friendly? I don’t think so. We have taught our machines to fly magnificently. Let’s concentrate on pilots.

National Post

The danger of blue skies

[Image: asiana.jpg?w=620]

Let me engage in the kind of idle speculation that infuriates the Air Line Pilots Association. News sources keep reporting that weather wasn’t a factor in the crash of Asiana Airlines Flight 214 at San Francisco International last Saturday. I think they’re wrong. Weather was very much a factor. In bad weather this accident wouldn’t have happened.

In bad weather, chances are a computer would have flown every element of the instrument approach, not the pilots. The airmen would have concentrated on their instrument scan, there being nothing for them to see in the blustery murk outside. If target airspeeds hadn’t been met they would have noticed in time. They wouldn’t have been distracted by seeing where they were going.

To see where he’s going is an asset to a pilot, but a cloudless sky with 10 miles of visibility doesn’t turn white-shirted and gold-braided human components of automated flight systems into pilots; if anything, it turns them into sightseers. They may stop monitoring the system before they start flying the airplane. Last Saturday the crew set the auto-throttles at the desired speed for the approach, but then, perhaps engrossed by the unfolding vista of San Francisco, failed to notice until they were at an altitude of 500 feet “a lateral deviation.” It meant the aircraft was well below the glide path, the airspeed had decayed, the auto-throttles hadn’t been maintaining the targeted 137 knots, whether because they malfunctioned or hadn’t been set properly, but by then their jetliner was only at 200 feet, low and slow, the approach anything but stabilized, and it wasn’t until 16 seconds before crashing that they initiated a go-around, which was the right decision taken too late. The tail of the Boeing 777 touched a sea wall, perhaps as the pilots attempted to rotate. Two lives were lost in the flaming smash-up that followed and there were some serious injuries, but the human toll was light. About half of the 301 souls on board walked away from what the pilots thought for a fleeting moment was just a heavier than usual landing.

The powerful pilot union is furious with Deborah Hersman, Chairwoman of the U.S. National Transportation Safety Board, for introducing an unprecedented novelty at her agency’s press briefings. Rather than evading the media’s questions, she makes an attempt to answer them. Releasing information to the media as it reaches the investigators — say, data from flight recorders — is a departure for an investigative agency. Traditionally, press briefings are called to conceal information, not to reveal any, unless it is to spread disinformation or push a message.

The motives of those who would freeze or massage information isn’t necessarily sinister or self-serving. Early information, released prematurely to inexpert hands or sensation-mongers often results in misleading, even nonsensical coverage. The media want to be first, but to be first at the price of being ill-informed or plain wrong is in nobody’s interest.

In the case of Flight 214, these are the essentials we learned as soon as the NTSB found out:

The ground-based ILS (Instrument Landing System) serving Runway 28L on which Flight 214 was supposed to land was out of service. It meant the glideslope couldn’t be used. It plays no role of any kind in a visual landing. A Precision Path Indicator system, which does, was available to the pilots.

Bad weather flying has its own hazards but failure to look at the gages isn’t one of them

The four pilots on the flight deck were qualified to perform their assigned functions but not highly experienced with this model of aircraft. In the left seat the Pilot Flying was about halfway through his training on the Boeing 777 with 46 hours on type, while the Pilot Not Flying in the right seat, doubling up as the Training Captain, was on his very first mission in that role. The third pilot performed other cockpit duties and was not monitoring either the flight path or the instruments during landing, while the fourth pilot wasn’t required to be on the flight deck and wasn’t.

It was not known (or released) how many of the airplane’s functions were relegated to the computers on board, but the all-important function of speed control was assigned to the auto-throttles. To be of use, they need to be engaged. If they were, they may have malfunctioned; if they were not, the pilots did.

Flying in bad weather, the pilots would have monitored their altitude and airspeed closely. It’s a human tendency to concentrate on the best information available, which on a day of blustery murk wouldn’t be outside the cockpit window. Bad weather flying has its own hazards but failure to look at the gages isn’t one of them.

Should we leave fair weather flying to computers? That may be carrying things too far. Just keep in mind that unpleasant surprises usually come out of the blue.

National Post

Live in a way that is full of life... for yourself, for your loved ones, for your friends
08-20-2013, 11:19 AM
Post: #2
09-04-2013, 11:26 PM
Post: #3
Unstable...go around...

Fly to live,Live to fly.

Forum Jump:

User(s) browsing this thread: 1 Guest(s)