Posted on 07/07/2013 8:11:12 AM PDT by george76
A navigation system that helps pilots make safe descents was turned off at San Francisco airport on Saturday when a South Korean airliner crashed and burned after undershooting the runway ...
The system, called Glide Path, is meant to help planes land in bad weather. It was clear and sunny, with light winds, when Asiana
...
San Francisco International has turned off the system for nearly the entire summer on the runway where the Asiana flight crashed, according to a notice from the airport on the Federal Aviation Administration's Web site
(Excerpt) Read more at ca.news.yahoo.com ...
You got to the nut real good. I will take the NTSB a year to come to the same conclusion. One point, though; the PIC flew an unstable approach into the ground.
Every now, and again, whilst commiting aviation, I will come in high just to do a forward slip...ticks off the wife. “....but, dear, I was a little too high.”;-)
NOTAM=NOtice To AirMen. It is a reporting system that warns pilots of additional or temporary hazards to aviation in a specific area. In an airliner you would get those notices in your dispatching instructions. Changes in flight would come via a datalink in the aircraft. Before you reach your destination you check recorded weather and runway info via radio at your destination airport. All of those would include NOTAMS.
“At SFO, runway 29L has a 4-light PAPI system on the left side of the runway.”
It’s called a VASI (Visual Approach Slope Indicator) There are two groups of four lights spaced some distance apart on the approach end of the runway. If both sets of lights show “white” to the pilot, he’s high, if both show “red” he’s below the standard glides lope ( which is, at most airports, 3 degrees down). He’s on the glide slope when the far set of lights are white and the near set are red.
I have read in some local accounts that the plane had an unusually high rate of descent. The VASI would have been all red in this condition.
Very illuminating story. I’ve learned far more from Freepers than from the MSM
NOtice To AirMen...
“Did the controllers keep him high in altitude and not allow enough of a descent rate due to traffic departing under him (the four-post operation of a busy TRACON)?”
If they did, the pilot should executed a go around. He’s still the final decision maker in this regard. He’s still PIC and his decisions over rule ATC. I’ve landed at SFO many times on trips from the Orient. Bay Approach always takes inbound Pacific traffic down over Moffett which gives the aircraft a very long straight in approach to 28 Left. ( probably at least 15 miles).
Unless you're on fire, lose consciousness or have some critical part of the plane fall off while in the pattern or on approach, if you screw up by landing that short on a clear day with light winds, you have less than no excuse.
No, it looks ugly. 1300 fpm rate of descent is very scary. It really is almost twice what is required. A good rule of thumb is half of the ground speed. By that I mean 140 Knots over the ground gives about 700 fpm descent rate on the normal 3 degree glide path. 140 knots is pretty close to the approach speed for the 777’s at UAL (a little slower for flaps 30, a little more for flaps 25).
109 Knots at 100 feet (if I’m reading the numbers correctly) is very, very scary. Even if they would have cleared the sea wall, that is definitely tail strike speed. I don’t know if it was a 777-300, since the are slightly longer, they have a tail skid just in case.
That looks to me like a profile where the engines did not spool up. British Airways had a similar incident happen at Heathrow. They had ice crystals in the fuel lines that prevented spool up on their Rolls Royce engine on short final.
http://en.wikipedia.org/wiki/British_Airways_Flight_38
No, a VASI is two lights (or sets of lights), arranged along the side of a runway, in a "column".
PAPI (Precision Approach Path Indicator) is a set of 4 lights, arranged in a "row" on one side of the runway.
There is also a tri-color, single-light VASI. But, it is not used much in the US.
“Is “Glideslope” different from ILS?”
Glidelope is one component of an ILS system. It provides the vertical positioning. There is also a horizontal component that guides the plane to the threshold laterally. That component usually comes from a Terminal VOR.
But, they continued to bleed off airspeed and were too slow to check their descent at 600 feet.
However, I don't know why. There might have been a delay in spooling up the power, or they may have reacted too late.
“This is pilot error. Non-stabilized approach requires a go-around and he didn’t. You might question whether the controllers didn’t allow him time to descend or reduce speed, but it doesn’t matter. STABILIZED APPROACH, OR GO AROUND.”
Absolutely correct! Pilot in Command still has ultimate responsibility and authority to conduct a successful operation. He didn’t correct a high sink rate on final and decided to try to loose airspeed and kill the sink at the threshold. I was nearby in Sonoma County when it happened. Winds were very gusty out of the West. This is where you carry more power so you don’t drop out if a gust.
Red over white, doing alright.
white over red, you’re gonna be dead.
What my instructor said, anyways ...
I’m not a pilot and I can’t attest to the accuracy of the data, only the black boxes can but looking at the last few lines of the flight log provided by:
http://flightaware.com/live/flight/AAR214/history/20130706/0730Z/RKSI/KSFO/tracklog
suggests that the approach speed may have been too low.
Still it’s the responsibility of the PIC to land safely.
Controlled flight/descent into terrain due to instrumentation fixation, cultural reluctance of the other crew to say anything to the PIC, and failure to look out the windscreen ...
Been flying since 1996? Can’t blame the controllers if ya ask me.
I wonder what “Bitchin’ Betty” was saying to the crew? “pull up! pull up! terrain terrain terrain!” [ do triple 7s have Betty? ]
they used to be called VASI lights - visual approach slope indicators, but those ran linear, not lateral to the runway.
EASY to set your VFR approach, even at night.
Yes, as a matter of fact, Eric Swalwell (D, CA) was on several of the news programs stating that the sequester was the reason the ILS was slow in being upgraded.
Thanks for the info, I haven’t been in the cockpit for a few years. But as you point out VASI and PAPI accomplish the same function, providing the pilot with rudimentary glide slope information. This “crash,” failing any subsequent finding that there was a mechanical problem, is simply a pilot screw up! Just look at the descent data that one of the other posters put up. Vertical speed was all over the map! Just glad that more lives were not lost. From the look of the plane, they must have evacuated very quickly.
Well it makes one wonder if its been off that long with no crash what happened this time?
That’s half the fun of these thredes
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