allardjd 1,853 Posted February 13, 2009 Report Share Posted February 13, 2009 Quote http://my.earthlink.net/article/top?guid=20090213/49950c60_3ca6_1552620090213-623413254 They couldn't even get through one line in the article without using the term "nose dive". I hate it! This is a real disaster and ends over two years without a commercial air carrier fatality in the US. Icing is a possibility, but it's too early to say. It sounds as if it was a Dash 8 Q400. There were no survivors and one fatality in the home that was hit. I'm sure there will be a lot more information in the coming days. John Link to post Share on other sites
hurricanemk1c 195 Posted February 13, 2009 Report Share Posted February 13, 2009 Link to post Share on other sites
Longbeard 0 Posted February 13, 2009 Report Share Posted February 13, 2009 Very sad... http://www.buffalonews.com/home/story/577959.html http://www.wgrz.com/news/local/story.aspx?storyid=64153&catid=37 http://wcbstv.com/breakingnewsalerts/continental.airlines.crash.2.934393.html Link to post Share on other sites
mutley 4,497 Posted February 13, 2009 Report Share Posted February 13, 2009 I was very saddened by the news. There were some issues with the landing gear with the Dash 8, not that was instrumental this time but the aircraft has had some bad press recently. They fly overhead all day here and I have flown on one, a real shame for the families of the passengers crew and people on the ground. Link to post Share on other sites
allardjd 1,853 Posted February 13, 2009 Author Report Share Posted February 13, 2009 Just by dumb luck, not because they know anything about aviation, the media may have gotten it a little more correct than usual. The descriptions of the crash scene seem to indicate a high-angle descent and impact. Only one home was hit and others nearby were more or less unscathed. There's a pretty tight debris field and not much sign of an impact approach path. It's not clear yet whether it went in nose first or flat. Anyway, grudgingly, I am forced to admit that maybe "nose dive" may not be so inaccurate as it usually is when used by the mainstream media. Link to post Share on other sites
grth_bbtt 0 Posted February 13, 2009 Report Share Posted February 13, 2009 R.I.P to all onboard the flight and on the ground Link to post Share on other sites
allardjd 1,853 Posted February 13, 2009 Author Report Share Posted February 13, 2009 I just heard an NTSB briefing on TV. They have listened to the CVR tapes and looked at the DFDR data. The crew discussed ice that was forming on wings and windshield De-icing systems were on Gear was lowered 1 minute before the end of the tape Flaps 15 were selected 20 seconds after that Severe pitch and roll excursions were experienced immediately after the flaps were selected The crew attempted to retract the gear and flaps just before the end of the tape An interview with a former (retired) NTSB member suggested ice induced tailplane stalling as being a possibility. Given the data above, I wouldn't rule out a split-flaps condition either. This is all very preliminary... John Link to post Share on other sites
allardjd 1,853 Posted February 15, 2009 Author Report Share Posted February 15, 2009 http://my.earthlink.net/article/top?guid=20090214/49965de0_3ca6_1552620090214-467202639 Pretty good article.... "nose dive" debunked. Impact was flat, and probably pointed 180 degrees from the runway heading. Unclear if they deliberately turned or if they were in a flat spin, though the guys looking at the DFDR data should be able to clear that up pretty easily. Making a 180 on an inbound ILS course seems kind of unlikely, but the article seems to describe that as a possible ice removal technique - never heard of that one... I wouldn't rule out split flaps yet. A flat-spin in a Dash 8 from glide slope height, at night, in bad weather and carrying a load of ice does not sound like a fun way to spend the last minute of your life. I feel very bad for those pilots, who had to know what was coming. The line that says the Transportation Sec'y told a US Senator that the AC made a 180 degree turn at 5,000 ft. is puzzling, unless someone got the details wrong. They should have been nowhere near 5,000 ft at 6 NM from the airport. Stick shaker and stick pusher both actuated, but not clear at what point in time. John EDIT: I just looked at the approach plate. They were not yet at the FAF, which is only 4.4 NM from the threshold. Approach plate shows an outbound leg and procedure turn at > or = 2,400 and descending to no less than 2,300 on the inbound leg until intercepting the glide slope. They probably did not fly an outbound leg and procedure turn but almost surely got vectors to intercept the localizer. They should have intercepted the glideslope at 2,300 (or slightly higher) and have been down to 2,206 feet at the FAF which was still over a mile closer to the airport from the point of impact. Missed approach procedure only specifies going to 3,000 and they were a long way from the MAP. I don't know where that 5,000 foot business comes from. It sounds like politicians talking about something they didn't know much about. JDA Link to post Share on other sites
hurricanemk1c 195 Posted February 15, 2009 Report Share Posted February 15, 2009 I don't know where that 5,000 foot business comes from. It sounds like politicians talking about something they didn't know much about. Never do Link to post Share on other sites
mutley 4,497 Posted February 15, 2009 Report Share Posted February 15, 2009 Looks like pilot error as he broke company rules as the aircraft was under control of the autopilot when it went down - violating airline policy. Pilots are recommended to fly planes manually in icy conditions and required to do so in severe ice, said US National Transportation Safety Board (NTSB) investigator Steven Chealander. More here http://news.sky.com/skynews/Home/World-News/Buffalo-Plane-Crash-Aircraft-In-Autopilot-When-Landing-Violating-Airline-Policy-Rules/Article/200902315223240?f=vg Link to post Share on other sites
allardjd 1,853 Posted February 16, 2009 Author Report Share Posted February 16, 2009 That sounds plausible. Autopilots are generally pretty stupid devices, though generally get better the bigger and more complex the AC. If you want an example, take off in a heavily loaded most-anything and set a fairly high climb rate. Engage the AP and watch what it does. It will try to maintain that climb rate no matter how high the nose gets or how low the airspeed gets until it either stalls or runs out of trim. Better AC have better APs, and probably have more and better sensors and warnings. I ran across an AC recently that had an annunciator that alarmed as it neared the limit of pitch trim travel, alerting the pilot it was getting near the edge of the envelope. Does anyone know if the Dash 8 Q400 has autothrottles? I don't know but suspect not. What could have happened is that the AP just kept raising the nose and the airspeed just kept coming down as the weight increased and the wing efficiency decreased due to picking up all that ice. For most APs, if altitude is sagging, all they know to do is to crank in more nose-up trim. I've read before that if you're flying an AC with a load of ice, you're a test pilot, because you're flying a wing shape that no one else ever has. You have no idea what the new stall speed is, though it's a safe bet it will be higher than the old one. I know a guy who once managed to pick up a severe load of ice on an Grumman AA5 Tiger. He declared an emergency and landed straight in at a large airport that was luckily more or less right in front of him. He didn't make any radical turns and he landed it just as fast as it would fly. He's alive today to tell about it because he didn't slow it down until his wheels were on the ground. Link to post Share on other sites
allardjd 1,853 Posted February 16, 2009 Author Report Share Posted February 16, 2009 From AVWebFlash... Q400 Pitched Up 31 Degrees Before Crash The crew of the Bombardier Q400 that crashed in Buffalo on Thursday got a stall warning and the stick pusher engaged but still the aircraft pitched upward 31 degrees before turning almost 180 degrees and dropping onto a house in the Buffalo suburb of Clarence Center, near the outer marker for Buffalo Niagara International Airport. The sequence of events, which included a 45-degree dive with a 106-degree right bank ended 26 seconds later in the fireball on the ground, killing 49 people on the plane and one on the ground, the owner of the house. Although icing continues as a theme in the investigation, reporters were told at an NTSB press briefing on Sunday that the aircraft's anti-icing system had been on for most of the flight and, while both pilots discussed the "significant" icing their aircraft was experiencing, at no time did they use the "severe icing" descriptor that is the official notification of flight-threatening buildup. "We don't know that it was severe icing," NTSB member Steve Chealander told reporters. "They [the crew] didn't say that it was severe icing....The weatherman didn't say that it was severe icing." Initial reports suggested the aircraft, flying as Continental Connection Flight 3407 dove on the house but later reports said it crashed in a flat attitude. According to data released at the press conference, the last radar hit showed the aircraft with a forward speed of only 100 knots and it lost 800 feet in five seconds. The autopilot was on for part of the sequence and the engines were set to full power just before impact. Link to post Share on other sites
allardjd 1,853 Posted February 16, 2009 Author Report Share Posted February 16, 2009 http://www.foxnews.com/story/0,2933,493484,00.html There are a few snippets of new info in this article... The most significant one I see is that the de-ice systems were switched on 11 minutes into the flight and remained on for the entire flight. The NTSB describes that as, "...very conservative...". One piece that really puzzles me says... "At some point, the pilot switched on an anti-stall device that increases the speed of the plane by 20 knots and gives a pilot more margin to recover from a stall if it occurs." Does any one have a clue what that refers to? John EDIT: Could that be a media-garbled description of flaps? JDA Link to post Share on other sites
allardjd 1,853 Posted February 19, 2009 Author Report Share Posted February 19, 2009 From AVWebFlash... 3407 Pilot Error Suspected: WSJ Report Investigators studying last week's fatal crash of a Continental Connection Dash 8 Q400 in Buffalo, N.Y., now have found evidence that pilot inputs to the controls may have contributed to the airplane's stall, The Wall Street Journal reported on Wednesday, citing sources close to the investigation. The flight data recorders show that the flight was routine until roughly a minute before impact, when the crew lowered the landing gear and extended the flaps, according to the WSJ sources. Almost immediately, the airspeed bled off and the stick-shaker activated, followed by a stick-pusher that automatically lowered the nose. It appears the captain pulled back on the stick with enough force to overpower the pusher and added power, causing a 31-degree pitch-up. The wings immediately stalled, and the airplane whipped to the left, then entered a steep right turn. The pilots continued to fight with the controls, and they were starting to recover when they "ran out of altitude," according to the WSJ source. NTSB member Steven Chealander, speaking to The New York Times earlier this week, urged "caution about jumping to conclusions that it might be an icing incident." Fifty people were killed in the fiery crash, including one person on the ground. The NTSB investigation is continuing and no probable cause has been determined. Link to post Share on other sites
mutley 4,497 Posted February 19, 2009 Report Share Posted February 19, 2009 Oh boy, that is so sad. All in the heat of the moment and those aircraft cannot cope with those sort of angles. Link to post Share on other sites
allardjd 1,853 Posted May 13, 2009 Author Report Share Posted May 13, 2009 The link is a pdf of the NTSB transcript of the cockpit voice recorder and also includes all the radio communications to and from ATC. This is for the entire duration of the flight. It's long but is an interesting read... http://www.foxnews.com/projects/pdf/buffalo_cockpit_transcript.pdf My impression is that they were a couple of undisciplined, inexperienced, overconfident lightweights and seemed to be just going through the motions of the required checklists, etc. FAA regs require a sterile cockpit (no unnecessary conversations) below 10,000 feet. Though they seemed to comply during the climb, the entire cruise portion of the flight was mainly personal discussions of career, etc. That continued in the descent and approach phase. Though there is some discussion of the amount of ice on the windshield and leading edge late in the transcript, I didn't get the sense that they were very concerned about it. My impression is that they had no clue the ice had pushed them into a corner of the performance envelope until the very last minute. You may remember that the autopilot was flying until it disengaged at the very end. By not hand-flying in icing conditions (as recommended by the FAA and required by their company rules), they deprived themselves of the feedback that they'd have gotten by having to constantly add nose-up trim to maintain altitude as the ice drove them closer and closer to a stall. Surpisingly, what I've read recently from the latest NTSB hearing is that they now seem to be looking at this as a simple stall, not the ice-induced tailplane stall that was speculated about earlier. The expert witnesses now say that the pilot pulled back on the yoke and should have pushed forward to recover. The latter is correct for a conventional stall and is incorrect for a tail plane stall. It is possible to tell the difference between the two from the cockpit, but you have to be paying attention in the moments before it occurs or you won't have a clue. This is all morbid, but interesting. The NTSB is very concerned about commuter-class aircraft, particularly turbo-props because of their limited anti-icing and de-icing capability. Jets have much more thermal energy available from bleed air for those things. John Link to post Share on other sites
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