1977 Tenerife Disaster

[rjemery]

As we all know too well, two 747s collided on the runway in heavy fog at Los Rodeos Airport, Tenerife, in 1977. Since the PanAm aircraft was just taxiing, I would not have expected it to have its radar operating, but if the KLM plane was taking off, when would it have normally turned on its radar?

Had that radar been enabled on takeoff, would it have showed an aircraft ahead?

[gg190]

I presume it's the weather radar in the nose of each aircraft your referring to?

This would not have not have been switched on in either aircraft. Weather radars are off whenever the aircraft is on the ground as they can be harmful to people in close proximity due to their high power. They switch on automatically when the aircraft has left the ground.

Even if this had been switched on in either aircraft, the other aircraft would not have been visible on it.

The only radar that could have influenced events in this crash is ground radar, which was not installed at the airport.

[Noyade]

Interesting thread.
I'm a novice, so please be gentle.

According to what I've read the KLM and PanAm turned the corner (so to speak) and headed down the runway...close together...right?

Question one. How is it then that KLM manages to reach the end of the runway, turn 180 degrees, wait a period, begin to roll and nearly take-off whereas Pan Am only just manages to reach Taxiway Charlie 4 in the same time period? Was KLM 'hooning' down the runway?

Question two. If he was, why not (get permission first) just simply apply full power and take-off from the right of the illustration/runway. Boeing 747s...no need to look at a windsock...?

Or is it not as simple as that?

Cheers
Graeme.

(Sorry 'bout the Vulcan bomb holes in the runway...hole-punch).

http://img809.imageshack.us/img809/746/holepunch.jpg (http://img809.imageshack.us/i/holepunch.jpg/)

[forget]

Weather radars are off whenever the aircraft is on the ground as they can be harmful to people in close proximity due to their high power. They switch on automatically when the aircraft has left the ground.

Was KLM 'hooning' down the runway?

How about both of you doing some very simple research before making yourselves look very foolish. :mad:

[Phileas Fogg]

The Panam needed to backtrack the runway to exit on to a taxiway closer to the threshold.

ATC in Tenerife-North was infamous in those days, a Dan-Air B727 in to the side of a mountain etc, and the Panam crew had difficulty understanding ATC instructions and this probably slowed down their progress wheras they had not exited the runway as the KLM started it's roll.

Apparently crew fatigue played it's part upon the KLM crew which was apparently commanded by one of KLM's more senior management Captains.

[gg190]

Weather radars are off whenever the aircraft is on the ground as they can be harmful to people in close proximity due to their high power. They switch on automatically when the aircraft has left the ground.

How about both of you doing some very simple research before making yourselves look very foolish.

Unless my ATPL course was wrong then the statement I have made is correct.

[rjemery]

How is it then that KLM manages to reach the end of the runway, turn 180 degrees, wait a period, begin to roll and nearly take-off whereas Pan Am only just manages to reach Taxiway Charlie 4 in the same time period?

When the KLM 747 was moving down the runway, it had relatively clear visibility, at least at the start and could move at normal or near normal taxiing speed.

When the PanAm 747 started taxiing, the fog settled over the runway, cutting visibility. Since the PanAm aircraft was preparing for a left turn, it also was moving at a much slower rate, cut even lower because of the fog. The fog was so thick, the PanAm crew could barely see the ground in front of them, let alone the C3 or C4 turnoff.

[forget]

gg190 Unless my ATPL course was wrong then the statement I have made is correct.

Sorry to tell you - both points covered here from earlier Prune discussions.

Page 93 of the Pilots' Guide for Collins WXR 700X Weather Radar System states: "There is no apparent reason for restricting ground use - however it would be prudent to turn off the weather radar at the gate (Off, Standby or Test) and enable the weather radar after leaving the gate.

[763 jock]

I should apply for a refund on that ATPL course then.:ok:

[WaterMeths]

Just to stop the bun fight guys ....


Quite correct - the weather radar is normally put on during the taxi out to the runway - great for looking out before take off into Wx - planning diversion from the standard departure etc....

In the case of the KLM seeing the other a/c on weather radar - not a chance - all he would see was ground clutter - a return of mainly red on the whole screen with the dish pointing along the ground.

In our company we have the radar tilted to 5 degrees up to avoid ground clutter.

Hope this helps the thread

Cheers WM

[Dave Gittins]

One one day at Denver having arrived from Vegas on a Ted A-320, I asked the Capt why he turned off the aircraft - ATC audio feed which United broadcast through the entertainment system just before take off.

His response was that sittin' at the threshold he could see the biggest mother f***er of a thunderstorm sitting on our climbout path and he didn't want to frighten the pax when he reported what he saw and called to vector round it.

So his was on before take-off and obviously looking up. Is it like a transponder .. turn on when entering the runway ?

[forget]

The Collins WXR-2100 radar system falls well below the 10 mw/cm2 standard. However, it should be noted that there is some disagreement that the 10 mw/cm2 standard is low enough. Microwave ovens represent a more public safety concern and their leakage standard has been set at 4 mw/cm2. The WXR-2100 power density is half or less than that of the microwave oven standard.

Para 6-44. http://www.smartcockpit.com/data/pdfs/flightops/aircraft/Collins_WXR-2100_Operator's_Guide.pdf

The referenced FAA Advisory Circular 20–68B is well out of date and does say that WX Radar is dangerous. The old systems were, to a degree; current models - not at all. Your ATPL courses may have used the FAA Circular.

[Dave Clarke Fife]

So his was on before take-off and obviously looking up. Is it like a transponder .. turn on when entering the runway ?

It is turned on or off whenever the pilot wants it in the on or off position. If the weather gives cause for concern then it is switched on and on our Airbus type the tilt is initially set to 5 degrees up pitch unless it has the newer auto tilt function which sets the tilt angle to optimize the weather radar detection.

[Phileas Fogg]

To further clarify ..... the KLM taxied first and needed to backtrack to the runway threshold to do a '180' before taking-off. The Panam taxied out after the KLM but needed to backtrack then exit on to a taxiway, to get out of the frigging way, to allow the KLM to take-off.

The Panam crew had difficulty understanding ATC in respect of which turning they needed to take off the runway, this confusion went on for a while, the KLM merely needed to follow the runway centre line, he didn't need to count turnings etc. hence why he was faster than the Panam.

[JEM60]

According to what I heard re the CVR tapes, The KLM Captain started his take-off run, and the First Officer definately seems to have had some doubts, and said 'Is he clear then, that Pan-Am?' and the Captain replied with an emphatic 'Yes'. The rest is, sadly, history.

[Phileas Fogg]

There's 6 pages of it here:

1001 Crash - The Tenerife disaster (http://www.1001crash.com/index-page-tenerife-lg-2.html)

[Shaggy Sheep Driver]

Wx radar is just like your TV - it has an on/off switch!

And no, even if 'on' as others have said it'd only see clutter on the ground, unless tilted 'up' when it obviously wouldn't see anything on the ground anyway. It's not a suveillance radar and isn't designed to detect aircraft, especially at close range. That's what TCAS is for! (Or preferably, ATC).

It's specified to show (unsurprisingly)..... weather sytems! And some obvious ground features like coastlines if tilted down when airborne.

[rjemery]

Some of the posts herein that answered follow on questions did not clarify if the answer applied to today's ops environment or what KLM/PA/B747 had in place in 1977.

Regardless, I would like to broaden my original post.

Whether in 1977 or now, I take it commercial aircraft did not have a radar system to see planes around them. Since most of the flight time was at FLs above the clouds, the pilot and copilot could probably visually see what's ahead of them by day, and if the aircraft were illuminated, what's ahead by night. To wit, no radar system needed. Is my reasoning correct?

With all aircraft now using transponders to identify themselves, is there an on board system today that maps where other planes are in the vicinity around a given plane? If so, how far out? Does the transponder also flash FLs?

Also at night, is it standard practice to fly dark? I know Air Force One frequently does, and it was reported KAL 007 also was dark -- no wing or tail lights whatsoever, but that could have been Soviet propaganda to help justify the downing of that aircraft.

[BOAC]

To get a correct answer to your original question, start at post #10.

To wit, no radar system needed. Is my reasoning correct?

Partly. It has never been the case that civilian aircraft should have to use their own radar to avoid collision. It happens, however, that weather radar will actually paint other aircraft once you are at reasonable height.

With all aircraft now using transponders to identify themselves, is there an on board system today that maps where other planes are in the vicinity around a given plane? If so, how far out? Does the transponder also flash FLs?

Yes, out to around 30 nm. It is called TCAS. FL information is available on some installations.

Also at night, is it standard practice to fly dark? I know Air Force One frequently does, and it was reported KAL 007 also was dark -- no wing or tail lights whatsoever, but that could have been Soviet propaganda to help justify the downing of that aircraft.

No.

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[Phileas Fogg]

rjemery,

What is your point? This isn't 'Spotters Corner', what happened happened due to an unfortunate combination of circumstances, please have respect for those, and the relations of, who lost their lives and not nit pick in to "what if?"

[PPRuNe Pop]

Please use the search system, there is a much detailed thread on this incident.

This one is now closed.