Airport landing system off when plane crashed in San Francisco

Reuters ^ | July 07, 2013 | Peter Henderson and Dan Levine

[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

[IFly4Him]

Regarding instrument approaches, the glide slope is associated with the VHF frequency that defines the localizer course on an ILS. A glide path gives vertical guidance on a GPS approach but it is derived from a combination of positioning, geometric altitude and ground based signal augmentation. From the pilot's perspective they are applied and flown in a similar fashion.

Regarding visual approaches, the term glide path predates the use of GPS and was a generic term for vertical guidance given by visual cues like a light based system or even the pilot's sense of depth perception.

A good SOP on a nice day is to use a GPS GP as a background reference even if you're technically doing a visual approach.

I have landed on 28 at SFO several times. Given the weather, they were probably doing "Bridge Visuals" but it's still a good idea to have a backup.

[justlurking]

No, the lateral guidance for an ILS comes from a LOC, or localizer.

A LOC only provides guidance for 10 degrees either side of the runway centerline, while a VOR can provide guidance for the full 360 degrees around it.

[B4Ranch]

See http://www.freerepublic.com/focus/f-news/3039996/posts?page=22#22 and 50.

[vette6387]

You’e right, it’s been too long.

[NormsRevenge]

Thanks.

Shades of Maxwell Smart..

missed it by that much.

[SkyDancer]

Was watching the video of that landing. Pilot hit short, nailed the shoreline rocks then everything went to hell after. So far I’d call it pilot error but since all the data isn’t in I’m holding back ...

[Kbiro]

Lear about Glide Path here:
http://www.pilotfriend.com/training/flight_training/nav/ils.htm

“Brief description

The ILS usually consists of a Localizer, Glide Path, and Markers(OM, MM, & IM).

Localizer: This equipment provides lateral guidance to the runway centreline from about 5nm out.(five nautical miles).

Glide Path: This equipment provides the aircraft with a glide angle - usually 3 degrees. The Localizer and Glide Path combine to bring the aircraft to a point where the aircraft is 50 feet high at the runway threshold (decision point).

Markers:
1. The Outer Marker at approximately 5nm helps the a/c adjust its course and height.
2. The Middle Marker is located at approximately 3500 feet uand used similarly.
3. The Inner Maker at 1000 feet is used only for Category II operations.

Exceptions:
There are always exceptions and here are some main exceptions.
1. DME & GP (Distance Measuring Equipment & Glide Path) when it is impossible to have Markers.
2. DME & Localizer when there is no GP for whatever reason.
3. Offset Localizer. In this case the Localizer is not on the runway centreline, but offset and lined up to bring the aircraft over the threshold at decision height. Decision height is 50 feet at threshold.”

And by the way, it is 28L and not 29L.

[justlurking]

I have never heard it called glide PATH before now. It has always been glide SLOPE, and even the article you cited uses both terms almost interchangeably. A hint: the FAA uses GS in their NOTAMs.

In any event, it doesn’t work the way the article describes it. It is an analog system, not computerized. And it doesn’t calculate the plane’s rate of descent. It simply broadcasts a narrow beam at about a 3 degree angle from the landing zone, back up the approach path. A relatively simple receiver in the cockpit indicates only whether the aircraft is above or below the glide slope.

Maybe some day, the news services will actually hire someone competent to write articles about aviation topics. But, I am sure they are completely knowledgeable about all the other topics they write about, like law, economics, guns, etc.

[justlurking]

I am putting together a few graphs from the FlightAware data posted earlier. I think you’ll be ale to see what happened, absent mechanical failure.

I should get them posted tomorrow.

[SkyDancer]

Hey thanks for doing that. Will it be a side view of the landing graph showing glide slope?

[justlurking]

Yes. It is the descent path, and I have added a line representing a 2.85 degree glide slope. That’s the angle reported for the 28L PAPI. You can see how they were too high, and then over corrected.

I am also building ones for vertical rate, and ground speed. That will really open your eyes.

All will be based on distance from runway threshold.

I believe I can also reconstruct the flight path. The plane made a 220 descending left turn onto final approach.

[SkyDancer]

This I have to see. Thanks!!!

[wastedyears]

I checked YouTube for video of it, but didn’t find anything. Where’d you find video?

[Yosemitest]

"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."

It would be a "CONTRIBUTING FACTOR" or "CONTRIBUTING FACTORS", but you're absolutely correct.

The final responsibility is in the lap of the Pilot In Command of the aircraft.
He can refuse the control instruction, due to Safety of Flight.

But he better be able to back it up later, when he has to answer for it,
and he better tell the controller that he is UNABLE to comply with the Instruction due to (reason).

Sorry for the delayed response, but the phone line's been OTS since the 7th of July and that takes out my internet connection.

[Yosemitest]

My phone/internet has been out from the 7th of July until now, due to lightning burning out the main exchange box for the phone company 7 miles away.
Thanks for the comment, and by now we've seen Fox News and the NTSB report.
They said the approach set him up on a 17 mile final and their graphic showed a good descent until about 3/4 of the way in, at which he leveled off for a short period.
Then the descent went steep and it went downhill from there.

[Yosemitest]

I first learned of these NOTAMS from NonValueAdded's comment #386.

"KTVU talking about the NOTAMS now ... out for about a month - normal visual glideslope equip is inoperable due to construction. Pilots expected to eyeball it in. PAPPI - bank of lights - was out."

Notice XHogPilot comment #406:

" The ILS for both RWY 28L and 28R have been inoperative for several days. It is likely the pilot was not aware.

https://pilotweb.nas.faa.gov/PilotWeb/notamRetrievalByICAOAction.do?method=displayByICAOs&reportType=RAW&formatType=DOMESTIC&∓retrieveLocId=KSFO&actionType=notamRetrievalByICAOs

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

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

So they were out effective from 2013 June 1 1400Z thru 2013 August 22 2359Z.

HOWEVER ... Notice

FAA INFORMATION EFFECTIVE 27 JUNE 2013

Runway 10R/28L

Dimensions:	11381 x 200 ft. / 3469 x 61 m
Surface:	asphalt/grooved, in good condition
Weight bearing capacity:	PCN 80 /F/B/X/T
Runway edge lights:	high intensity
	RUNWAY 10R		RUNWAY 28L
Latitude:	37-37.577402N		37-36.702548N
Longitude:	122-23.586325W		122-21.500520W
Elevation:	7.2 ft.		12.7 ft.
Gradient:	0.1%		0.1%
Traffic pattern:	right		left
Runway heading:	100 magnetic, 117 true		280 magnetic, 297 true
Displaced threshold:	no		300 ft.
Declared distances:	TORA:11381 TODA:11381 ASDA:10704 LDA:10704		TORA:11381 TODA:11381 ASDA:10981 LDA:10681
Markings:	precision, in good condition		precision, in good condition
Visual slope indicator:	4-light PAPI on left (3.00 degrees glide path)		4-light PAPI on left (2.85 degrees glide path)
RVR equipment:	touchdown, midfield, rollout		touchdown, midfield, rollout
Runway end identifier lights:	no		no
Centerline lights:	yes		yes
Touchdown point:	yes, no lights		yes, no lights
Instrument approach:			ILS/DME
Obstructions:	87 ft. tower, marked and lighted, 3875 ft. from runway, 950 ft. right of centerline, 42:1 slope to clear		none

So ... NOTAMS

!SFO 07/048 SFO RWY 10L/28R CLSD WEF 1307062310
!SFO 07/047 SFO RWY 10R/28L CLSD WEF 1307062309
!SFO 07/046 SFO RWY 28L PAPI OTS WEF 1307062219

Went into effect from July 6 at 2320Z, 2309Z, and 2219Z time respectively.

In my opinion, the PAPI were really OTS earlier because they were turned off due to construction, to prevent "landing too short" with the 300 foot displaced threshold.

Then, the NOTAMS were reissued because of the crash and the fact that they were destroyed or damaged.

[Yosemitest]

Wires or Power Lines killed someone recently in Mississippi.

[bert]

So what.....

The pilot must fy the airplane. He didn’t

He failed to achieve a proper glide path and he landed short....... that’s all there is to it. He should have landed a little long and avoided the problem.

The rubber on the runway is testimony that many, perhaps most, pilots allow a margin of safety beyond the numbers

[justlurking]

The NTSB had a press conference a couple of hours ago.

In the interviews with the pilots, they described the PAPI as operational.

[Yosemitest]

Career watch sups HAVE to cut the mustard at places like Osan AB and Kunsan AB ROK, as well as Eglin AFB and Duke Field, of which, I've not only been certified, but worked them all for several years.

Most of the office staff I observed in the FAA with two exceptions, couldn't separate two flies with a screen door, let alone control traffic.
And most controllers I've observed, unless they're catching the busier waves every day, grow a lack of proficiency rapidly and get scared to work the rushes, and suddenly become ill or have an appointment to go to.
The questions stand.

After 30 years of Air Traffic Control experience, most as Tower Watch Supervisor in the USAF, this was a Pilot Error Crash.
The pilot came in too steep, with too much airspeed to bleed off, so he put it into a stall position to get rid of the airspeed.
But he stalled it out and got lucky that he belly landed it into the underrun, and the closed portion of the runway, before the landing threshold and leaving a portion of the tail in the bay.

Both the PAPIs and the Glideslope were NOTAMed off due to the displaced landing threshold.
Had they been on the point of touchdown would have been too short for a safe landing.

But what I'd like to know is the compression rate and control instructions from the air traffic controllers starting with his descent from SF Center, through SF TRACON to the handoff to the tower.
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)?
And did the controllers keep his speed up with their control instructions, until too short of a final when they handed him off to the tower, and not allow him time to bleed off the airspeed, due to the arrival rate of aircraft they were shoe-stringing down final at that time?