Plane carrying Polish president Lech Kaczynski crashes near Russian airport, CONFIRMED DEAD, page 24
Pages: <<  21    22    23    24  >>
ATS Members have flagged this thread 133 times


reply posted on 14-4-2010 @ 09:47 AM by weedwhacker
reply to post by BobAthome


'Bob', you're talking here about a Russian-built Tupelov 154, design originally circa late 1960s. The Polish Air Force VIP jet that crashed was the Tu-154M 'Lux' version, built sometime in the 1980s.

Unlikely it would have the sort of sophisticated avionics that include an AutoLand technology. It DID have what we call 'enhanced GPWS', also called 'TAWS'...this is a GPS-linked system that has a database of terrain heights, and man-made obstructions world wide. So, fairly updated. HOWEVER, in the vicinity of the airport, and when the airplane is in the landing configuration, the warnings might not activate, unless way off course, and headed for hills of known obstructions. Trees are NOT programmed in, as it assumes, with gear and flaps extended, that pilot intends to land, and that pilot is avoiding trees.

Further, AutoLand is not available at all airports, and on all runways. It is a very, very specific procedure, and requires more precise ground-based equipment, as well as the onboard equipment.

Onboard requirement for full AutoLand include, among other things, a tripple-redundant AutoPilot system. (Terms 'fail/passive' and 'fail/active' also are important, and define certain visibility minima, and operating parameters).

There is ALWAYS a minimum visibility requirement for AutoLandings, and that is covered in special procedures and training for flight crews who become certified to conduct them.


Tu-154M
The Tu-154M and Tu-154M Lux are the most highly upgraded version, which first flew in 1982 and entered mass production in 1984. It uses more fuel-efficient Soloviev D-30KU-154 turbofans. Together with significant aerodynamic refinement, this led to much lower fuel consumption and therefore longer range, as well as lower operating costs. The aircraft has new double-slotted (instead of triple-slotted) flaps, with an extra 36-degree position (in addition to existing 15, 28 and 45-degree positions on older versions), which allows reduction of noise on approach. It also has a relocated auxiliary power unit and numerous other improvements. Manufacture continued through 2006, and there is still limited manufacturing as of January 2009.(photo link) Max. take-off weight increased first to 100,000 kg (220,462 lb), then to 102,000 kg (224,872 lb). Some aircraft are certified to 104,000 kg (229,281 lb). Tail numbers are 85616 (prototype), production aircraft from 85606 and on (except 85804, which is re-imported Tu-154B-2). About 320 were manufactured. Mass production ended in 2006. No new airframes have been built since the early 1990s, and production since then has involved assembling airplanes from components on hand. This is the most widely used version in the former Soviet states.


en.wikipedia.org...


reply posted on 14-4-2010 @ 09:52 AM by weedwhacker
reply to post by AskTheQuestion


I know.

That's why I was responding to the OTHER ATS poster's question.

Your points are all valid, but the fact is the Captain decided to attmept to continue the approach, despite it being below minimums.

As I said, there is a certain arrogance in pilots' attitudes (I know this, because it describes me, too).

That Tu-154M was operated by the Polish Air Force, too. Just as OUR VIP airplanes are flown by USAF.

BUT, the pressure was on him to get there. He took too much risk, maybe overconfident for some reason.

I don't knwo what type of approach they were using, would be helpful if someone can find an IFR approach plate for Smolensk.....then I can tell you more.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

OK, to edit here, I have more info.

Researching it, I can't find actual Airport information, as to the types of facilities it has for instrument approach procedures, but I DID find articles that tell me all I need to know:

On the face of it, the Smolensk accident has the hallmarks of the classic attempt by pilots to descend below minimum conditions in an attempt to land in bad visibility. It is being assumed by professionals that the Polish Air Force captain was under heavy pressure to get his plane-load of top brass to the historic ceremony at Katyn. The desire to land at all costs is known in the trade as "get-there-itis" and pilots are trained to resist it. But there are unanswered questions.
........

According to the Russian authorities the crew of the Tu-154M were making a fourth attempt to land. Fog covered the area, but visibility of a few hundred yards was reported. Standard rules for airlines require crew to give up after two attempts and divert to an alternate destination. If the Russian report is right, the crew were pushing it. But new reports today suggest that this may have been their first approach after circling the field three times. They were of course operating under military, not civil airline, conditions.


OK, here's the important bit:

The Smolensk North military airfield lacks an instrument landing system (ILS), the equipment that allows aircraft to descend very low in cloud on the approach to the runway. A civilian plane at Smolensk would normally be making a "non-precision" instrument approach, based on the "NDB" radio beacon at the field (it is not equipped with a more precise VOR beacon). This would require that the pilots spot the runway surroundings ahead and before they descend below a safe minimum height of a few hundred feet. Experts are saying today that a standard non-precision approach in the weather prevailing at Smolensk would have been unlikely.


The NDB is the absolute WORST, in terms of situational accuracy, of any navigational aid used in aviation. The standards for an instrument approach based on an NDB as sole navigation are quite restrictive. Especially, minimum visibility required. You MUST be able to see at least what we call the "landing environment" (the Approach Lighting System, 'ALS', qualifies for we US operators) in order to continue an approach, and to descend below MDA. PLUS, it is very, very difficult to align visually, with the runway, in poor visibilty. You're moving at around 130-140 knots, remember. Things happen fast.

This crew decided to "risk it", and sneak down below MDA, in hopes of picking up some visual cues and making it in. Sometimes this is referred to as 'scud-running'.

Article goes on, however:


There is an alternative. The pilots may have been on a military Precision Approach Radar (PAR) -- a method used very rarely in civil aviation. The Russians have not confirmed that this was the case, but their statements suggest it. With PAR, the pilots are talked down by controllers using very acurate ground-based radar. The approaching aircraft is kept on the glideslope by verbal instructions -- "high, low, left right" and so on. That was, for example, how planes landed at Sarajevo in poor weather during the siege in the mid-1990s.

We know that the Russian military controllers were closely monitoring, if not guiding, the approach because they told the Polish crew that they were descending below the glide-path and advised them to give up, according to officials. The controllers advised them to try another destination, but the captain has final authority. The airliner hit the trees a kilometre from the runway and slightly north of its normal approach course.


I've never done a real PAR, only in the simulators. Still, even a PAR requires certain minima, in terms of reported visibility. For same reasons stated above.

I was trying to find examples of NDB approaches in the US, but most have been decommisioned...with the advent of GPS, it is actually much better, and becoming more common every day.




[edit on 14 April 2010 by weedwhacker]


reply posted on 14-4-2010 @ 10:46 AM by weedwhacker
reply to post by BobAthome


Well, if you just look up the Polish Air Force inventory, you begin to see the problem:

en.wikipedia.org...


reply posted on 14-4-2010 @ 01:05 PM by AskTheQuestion
reply to post by weedwhacker


That article reaffirms the 'fourth attempt' theory. Which was shown to be inaccurate up thread.


reply posted on 21-4-2010 @ 09:38 PM by blueprint of the fall
gazbom.blogspot.com...

The man who filmed the plane crash was assassinated!

Cant post new thread because i don't have enough post.I hope some one else see's this......


reply posted on 23-4-2010 @ 09:09 PM by AskTheQuestion
reply to post by blueprint of the fall


Yeah, it's all just a coincidence. Nothing to see here people, move along.
Pages: <<  21    22    23    24  >>    ^^TOP^^