isanb Posted June 30, 2009 Share Posted June 30, 2009 (edited) meaby i'm going to say something stupid cause i know nothing about plane. a plane fly because of the amount of air going under the wings, no ? So what is important is the air speed and not the ground speed. If you put a plane in front of a giant fan , and if there is enough air speed to take off, the plane will fly and they will be no ground speed at all. Is it correct ? Carib please explain Edited June 30, 2009 by isanb Link to comment Share on other sites More sharing options...
LaoPo Posted June 30, 2009 Share Posted June 30, 2009 ...what a useless discussion. The plane went down and nobody knows how and why and it's doubtful if we will ever know as the black boxes haven't been found so far and they have only 1 or 2 days to go before the signaling from those boxes stop...forever. Apart from that: there's not a single person on earth who knows everything about planes. It's a combination of know-how of thousands of engineering specialists who're creating and building those complicated pieces of machinery. If it was that easy a laundry lady could do the job and tell us what went wrong. Let's stop this nonsense...it doesn't make sense. LaoPo Link to comment Share on other sites More sharing options...
Carib Posted June 30, 2009 Share Posted June 30, 2009 meaby i'm going to say something stupid cause i know nothing about plane.a plane fly because of the amount of air going under the wings, no ? So what is important is the air speed and not the ground speed. If you put a plane in front of a giant fan , and if there is enough air speed to take off, the plane will fly and they will be no ground speed at all. Is it correct ? Carib please explain Yes Isanb, you are correct. It is like a kite on a rope. Ground speed is zero, but airspeed is enough to hold it up there. Not enough wind, the kite will fall to earth. To much wind and the kite will be torn apart. Most of us started doing aerodynamics when we were young... Link to comment Share on other sites More sharing options...
Lopburi99 Posted June 30, 2009 Share Posted June 30, 2009 (edited) 75 MPH head wind and 75MPH forward movement against said head wind = 150mph airspeed.100 mph into 100mph headwind is 100mph airspeed, but zero ground speed. As reflected in GPS LORAN Radar. My point was not about air speed or head winds, tail winds, side winds, vortex nor shears, but strickly reading inertial MOVEMENT of the plane relative to it's previous movement. Which does have some relevance to what the plane is doing from moment to moment. Unless the plane is moving 100% into 100% or more headwind, it is making forward progress. If that progress or is increased or diminished will result in some inertial differentiation. IMO this could have helped this poor pilot in the video, if displayed in a logical way; was their progress increasing or slowing, they had no clue. Reminds me of when I was a student pilot many years ago. My instructor and I were practicing "slow flight" on a windy day. We had a north heading but with the strong headwind we were actually traveling southward. One could say we had negative ground speed. We flew from Detroit Michigan to Toledo Ohio "backward"! Edited June 30, 2009 by Lopburi99 Link to comment Share on other sites More sharing options...
isanb Posted June 30, 2009 Share Posted June 30, 2009 Thank you carib i was just asking a confirmation because i didn't understand why they were talking about ground speed and GPS. Link to comment Share on other sites More sharing options...
Carib Posted June 30, 2009 Share Posted June 30, 2009 GPS, inertial, Loran, DME, radar etc. all give speed over the ground, which is affected by winds aloft and air density. Flight characteristics however depend entirely on apparent speed through the air in which the aircraft is flying, so unfortunately there is no substitute for actual air data from a pitot tube. Not true. GPS is used in secret military usage, you do not know off my friend. It's not only your car TomTom. Did you really think the media tells you everything? One of my friends is a Co-Pilot on KLM, he confirms this. A measurement with GPS is always correct. A: Fixed measurement points on land, using mostly around 34 satellites or more. B: The planes actual speed is calculated up on these reference points, using fixed data. There is no such thing as land or air speed. An object is always travelling with the same speed. There no way this can be wrong. Why do you think the U.S.A is building a orbital defence system against rockets, planes and whatever, because the measurements arent correct? Total and utter rubbish. Since there is no difference between land and airspeed tell me how an aircraft can have in indicated speed of 150 miles, and a groundspeed of 75 miles. ?? I am looking forward to see you explain that with your own theory of course. The Pitot measures AIR speed, not Airplane speed. And there is no such thing as ground speed, ever seen the ground moving? Air is not an object. The plane is. So measuring from a fix point of the ground, you know the speed which the plane is travelling. For instance 960 km/h. And this is accurate. The difference in reading ( as you describe above ) is very logic, because you are measuring AIR speed. v=s/t Datsun, please. You are making the basic mistakes everybody makes when being confronted with this phenomena. One cannot use gps readings to keep an aircraft either up there, or to prevent it from overspeeding. GPS doesnot have a weather module build in to it which will sense the windspeeds at whatever level. Link to comment Share on other sites More sharing options...
Carib Posted June 30, 2009 Share Posted June 30, 2009 75 MPH head wind and 75MPH forward movement against said head wind = 150mph airspeed.100 mph into 100mph headwind is 100mph airspeed, but zero ground speed. As reflected in GPS LORAN Radar. My point was not about air speed or head winds, tail winds, side winds, vortex nor shears, but strickly reading inertial MOVEMENT of the plane relative to it's previous movement. Which does have some relevance to what the plane is doing from moment to moment. Unless the plane is moving 100% into 100% or more headwind, it is making forward progress. If that progress or is increased or diminished will result in some inertial differentiation. IMO this could have helped this poor pilot in the video, if displayed in a logical way; was their progress increasing or slowing, they had no clue. Anematic, I absolutely see what you are trying to say here, but it just doesn't work that way. What readout would you use to establish that, the course and distance you already left behind you? But it still wouldn't say anything about the present speed of the aircraft. Any shift of wind or a tiny nose up or down movement or power setting will have influence, and if those have occurred, how will you guess or even calculate your airspeed to make sure you stay within the aircrafts envelope. Link to comment Share on other sites More sharing options...
jackdanielsesq Posted June 30, 2009 Author Share Posted June 30, 2009 Apparently the craft had previously been given a clean bill of health by Airbus. Seems there is even more confusion amongst the airlines, let alone the folks who are being killed. BR>Jack "The question we are asking... is whether you can collect people in a normal way on French territory and then put them in a plane that does not ensure their security. We do not want this to happen again." However, a spokesman for the airline said poor weather was more likely to have been a factor in the crash than the condition of the plane. Yemeni Transport Minister Khaled Ibrahim al-Wazeer also told Reuters that the plane had recently undergone a thorough inspection overseen by Airbus and conformed to international standards. The crash prompted the European Union to highlight its own concerns about Yemenia's safety record, proposing a world blacklist of those carriers deemed unsafe. The EU already has its own list, and its transport commissioner, Antonio Tajani, said such a list would be a "safety guarantee for all". Another EU official told Reuters news agency there were concerns about the airline's "incomplete reporting procedure and incomplete follow-up" following 2007 tests on the aircraft that crashed, but that its record was improving. http://news.bbc.co.uk/2/hi/africa/8126576.stm Link to comment Share on other sites More sharing options...
Carib Posted June 30, 2009 Share Posted June 30, 2009 75 MPH head wind and 75MPH forward movement against said head wind = 150mph airspeed.100 mph into 100mph headwind is 100mph airspeed, but zero ground speed. As reflected in GPS LORAN Radar. My point was not about air speed or head winds, tail winds, side winds, vortex nor shears, but strickly reading inertial MOVEMENT of the plane relative to it's previous movement. Which does have some relevance to what the plane is doing from moment to moment. Unless the plane is moving 100% into 100% or more headwind, it is making forward progress. If that progress or is increased or diminished will result in some inertial differentiation. IMO this could have helped this poor pilot in the video, if displayed in a logical way; was their progress increasing or slowing, they had no clue. Reminds me of when I was a student pilot many years ago. My instructor and I were practicing "slow flight" on a windy day. We had a north heading but with the strong headwind we were actually traveling southward. One could say we had negative ground speed. We flew from Detroit Michigan to Toledo Ohio "backward"! Perfect example to illustrate the difference between air and ground speed ! Link to comment Share on other sites More sharing options...
cdnvic Posted June 30, 2009 Share Posted June 30, 2009 There is no such thing as land or air speed. Every pilot just broke out in chuckles upon reading that. In order to achieve the amount of lift required to maintain flight, air needs to move at a certain speed over the surface of the wing. The point at which there is not sufficient lift is called the stall speed. air⋅speed /ˈɛərˌspid/ [air-speed] –noun the forward speed of an aircraft relative to the air through which it moves. ground⋅speed /ˈgraʊndˌspid/ [ground-speed] –noun the speed of an aircraft with reference to the ground. http://dictionary.reference.com/browse/airspeed A tailwind reduces the relative speed of the air over the wing: Forward speed - tailwind = airspeed A headwind increases the relative speed of air over the wing: Forward speed + headwind = airspeed So if an aircraft's stall speed is 80 knots, and it has a tailwind of 30 knots, it must move at above 110 knots groundspeed to keep from stalling. No GPS can measure wind. This was not a design issue, it was an issue of a maintenance crew not following safety procedures, and a pilot who failed to check one of the basic parts of a pre-flight inspection that every trainee Cessna pilot is required to do. Link to comment Share on other sites More sharing options...
Datsun240Z Posted June 30, 2009 Share Posted June 30, 2009 Yes you guys are right, without the speed of the AIR they don't know if the airplane is travelling fast enough to maintain in the air. Okay, let's rest it for here. Link to comment Share on other sites More sharing options...
animatic Posted July 1, 2009 Share Posted July 1, 2009 Pertaining to the piteau valve mis readings. A inertial three light reference would have helped indicated which misreading speed gauge was more correct. One light means no change in momentum, red means losing momentum, green means gaining momentum. Then they could have seen at a glance that the speed was going up or down. And then decide which speed indicator is the best reference to planes motion, relative to itself. Even if the wind is pushing it backward, it still moving relative to itself. This was the info they were missing, what was the plane actually doing in space. Link to comment Share on other sites More sharing options...
TAWP Posted July 1, 2009 Share Posted July 1, 2009 GPS, inertial, Loran, DME, radar etc. all give speed over the ground, which is affected by winds aloft and air density. Flight characteristics however depend entirely on apparent speed through the air in which the aircraft is flying, so unfortunately there is no substitute for actual air data from a pitot tube. Not true. GPS is used in secret military usage, you do not know off my friend. It's not only your car TomTom. Did you really think the media tells you everything? One of my friends is a Co-Pilot on KLM, he confirms this. A measurement with GPS is always correct. A: Fixed measurement points on land, using mostly around 34 satellites or more. B: The planes actual speed is calculated up on these reference points, using fixed data. There is no such thing as land or air speed. An object is always travelling with the same speed. There no way this can be wrong. Why do you think the U.S.A is building a orbital defence system against rockets, planes and whatever, because the measurements arent correct? You must not be a pilot or even really interested in airplanes and aviation. Ground speed is what you are referring too as the airplanes relative speed against the ground. Also remember that the Earth spins(!). Airspeed is the airplanes relative speed against the local airspace it penetrates. Link to comment Share on other sites More sharing options...
Tywais Posted July 1, 2009 Share Posted July 1, 2009 There is no such thing as land or air speed. Every pilot just broke out in chuckles upon reading that. I'm a licensed pilot and suspect cloudhopper is also. Can't say I was laughing as much as being amazed. I remember coming in for a landing in North Dakota with a strong headwind. My airspeed was normal for approach to landing, but the ground speed obviously was not the same considering the fences at the end of the runway started going away from me. Windy state, North Dakota. Link to comment Share on other sites More sharing options...
Spee Posted July 1, 2009 Share Posted July 1, 2009 The difference in reading ( as you describe above ) is very logic, because you are measuring AIR speed.v=s/t I'm not a pilot, but I do have a degree in physics. Speed is a scalar quantity (ie., magnitude only). Velocity is a vector quantity (ie., magnitude and direction {whether 1, 2 or 3 axes}). My understanding is that aircraft have different instruments for measuring speed and for measuring velocity. In particular, as others have suggested, speed and velocity are relative terms (relative to the air for airspeed, relative to the ground for groundspeed and relative to a group of satellites for position via triangulation, and so on). None of this is here nor there with respect to the incident, as there are no data to analyze. Unfortunately, I would suspect that we will never know what actually happened. What the analysts do have is a history of possible related incidents, as well as the capability to simulate various types of conditions in a flight simulator and see how the test pilots and the aircraft react. Link to comment Share on other sites More sharing options...
animatic Posted July 1, 2009 Share Posted July 1, 2009 (edited) There is no such thing as land or air speed. Every pilot just broke out in chuckles upon reading that. I'm a licensed pilot and suspect cloudhopper is also. Can't say I was laughing as much as being amazed. I remember coming in for a landing in North Dakota with a strong headwind. My airspeed was normal for approach to landing, but the ground speed obviously was not the same considering the fences at the end of the runway started going away from me. Windy state, North Dakota. My friend and I flew a small plane into Pinkham Notch in New Hampshire once, expecting a smooth flight through in a few seconds. 10 minutes later we flew out backwards at full throttle, until he could throttle back and bear off and not lose both wings in the process. Edited July 1, 2009 by animatic Link to comment Share on other sites More sharing options...
jackdanielsesq Posted July 1, 2009 Author Share Posted July 1, 2009 There is no such thing as land or air speed. Link to comment Share on other sites More sharing options...
Datsun240Z Posted July 1, 2009 Share Posted July 1, 2009 Guys I said you where right a few post back okay? Link to comment Share on other sites More sharing options...
churchill Posted July 2, 2009 Share Posted July 2, 2009 Crash jet autopilot not able to fly plane at time of accident, investigation finds http://cnnwire.blogs.cnn.com/2009/07/02/cr...tigation-finds/ Link to comment Share on other sites More sharing options...
churchill Posted July 2, 2009 Share Posted July 2, 2009 AP: Investigators say Air France Flight 447 which crashed on June 1 killing 228 people was not destroyed in flight, say it fell vertically. Link to comment Share on other sites More sharing options...
jackdanielsesq Posted July 2, 2009 Author Share Posted July 2, 2009 That must have been terrifying!! BR>Jack Link to comment Share on other sites More sharing options...
Johpa Posted July 2, 2009 Share Posted July 2, 2009 So if you are driving 100 mph with your car into a 100 mph headwind, is it moving forward or not? You would be moving forward, but you would be needing significantly more energy, more gas, than if there were no wind. If you were driving based upon a gauge that only measured speed based upon gas consumption in a no-wind environment, your speed would slow down, and then if you were in the air, you might stall out. I may be no pilot, but don't they teach fundamental Newtonian physics in high school anymore?!? Link to comment Share on other sites More sharing options...
LaoPo Posted July 2, 2009 Share Posted July 2, 2009 Air France jet 'broke on impact' French investigators trying to find out why an Air France plane crashed in the Atlantic say they believe it broke up on contact with water, not in the air. They also found that the plane's speed sensors had been "a factor but not the cause" of the crash. All 228 people on the plane were killed when it plunged into the ocean en route from Rio de Janeiro to Paris on 1 June. Teams looking for the plane's flight data recorders will continue operations for another 10 days. Alain Bouillard, of the BEA accident investigation agency, said the crash had been an extremely difficult one to understand. But he said an examination of the recovered wreckage led them to believe the plane probably hit the water "in the direction of flight and with a strong vertical acceleration". The BBC's Transport Correspondent Tom Symonds said if the plane had broken up in the air, pieces of the fuselage would have been found twisted in a variety of directions. Instead they showed signs of compression in one direction, resulting from the plane hitting the water on its belly. Life jackets found in the wreckage had not been inflated, indicating that the passengers had little warning of a water landing. Many factors There has been speculation that the old-style speed sensors may have given the plane's pilots faulty information. But Mr Bouillard said they had been "a factor but not the cause" of the crash. In the wake of the crash, Air France accelerated an existing programme to replace speed monitors on its Airbus planes. Mr Bouillard said there was also concern about the length of the delay between the crew failing to contact air traffic controllers in Dakar, western Africa, as planned and the alarm being raised. He said his team was "still some distance away from establishing the causes of the accident" but that the search for the Airbus A330's data recorders would be extended to 10 July. The French investigation appears to contradict earlier reports attributed to Brazilian pathologists. They said last month that the injuries sustained by the passengers whose bodies had been found suggested the plane had been in pieces before it hit the sea. Mr Bouillard said France had not yet been given access to those autopsy reports. Search teams have recovered 51 bodies from the ocean but said last month that finding any more remains was "impossible". Story from BBC NEWS: http://news.bbc.co.uk/go/pr/fr/-/2/hi/europe/8130989.stm Published: 2009/07/02 15:18:50 GMT LaoPo Link to comment Share on other sites More sharing options...
Lopburi99 Posted July 2, 2009 Share Posted July 2, 2009 (edited) That must have been terrifying!!BR>Jack Imagine how the Challenger astronauts felt. My aeronautical engineer brother who worked for NASA and had worked with other astronauts said they all were conscious during their fall. I asked him if maybe they had taken a "pill". He said they had them available but most likely didn't have time to use them. What a horrifying situation. Edited July 2, 2009 by Lopburi99 Link to comment Share on other sites More sharing options...
jackdanielsesq Posted July 2, 2009 Author Share Posted July 2, 2009 We watched it for hours on end. Live BR>Jack Imagine how the Challenger astronauts felt. Link to comment Share on other sites More sharing options...
Carib Posted July 2, 2009 Share Posted July 2, 2009 It is the usual press sensationalist translation. The plane went straight down ... towards the surface of the water, very very fast," air accident investigator Alain Bouillard said. Well at least according to CNN.... The French investigator said: " l'avion a heurté la surfacec de l'eau en ligne de vol mais avec une composante verticale forte". Translated: The airplane hit the water surface with a `level attitude` but with an important/strong vertical component. The suggestion that it nose dived at an 90 degrees angle is pure sensation fuel, nothing more that that. Coming down vertically doesn't necessarily mean that it hit the water at a 90° angle or even close to it. The whole statement made by the French investigator has been taken out of it`s original meaning/text to suit the scoop and to be the truth for the uneducated ( in this aspect) crowd. No cause was mentioned, just possibilities which could have added to the crash. Nobody knows, there are just a few scenarios which may be likely, that is all. Link to comment Share on other sites More sharing options...
jackdanielsesq Posted July 2, 2009 Author Share Posted July 2, 2009 The lead investigator said this - "Flight 447 went down so quickly that passengers had no time to react" - what were passengers supposed to do? Jump?! There is still a huge divide between the 3 minutes of data sent to Air France in Paris, and +30,000 ft loss in altitude, before it crashed. BR>Jack Link to comment Share on other sites More sharing options...
Tywais Posted July 2, 2009 Share Posted July 2, 2009 The suggestion that it nose dived at an 90 degrees angle is pure sensation fuel, nothing more that that. Coming down vertically doesn't necessarily mean that it hit the water at a 90° angle or even close to it. Except for the case of a "flat spin". Link to comment Share on other sites More sharing options...
Carib Posted July 2, 2009 Share Posted July 2, 2009 The suggestion that it nose dived at an 90 degrees angle is pure sensation fuel, nothing more that that. Coming down vertically doesn't necessarily mean that it hit the water at a 90° angle or even close to it. Except for the case of a "flat spin". In a " normal spin" the nose `could be` 90 down, but in a "flat spin" the nose will align or be pointed at/with the horizon, of course give or take a few degrees during the motion. No airflow over the rudder, little airflow over the ailerons, so very hard to get out of it. Regards Link to comment Share on other sites More sharing options...
jackdanielsesq Posted July 2, 2009 Author Share Posted July 2, 2009 Precisely - my gut suggests it went into a power stall very early on. The million Dollar question is why they could not correct it expeditiously. There have been flight deck concerns with faulty ADIRU readouts still on the main monitor, which were giving misleading, faulty data, exacerbating the predicament. BR>Jack No airflow over the rudder, little airflow over the ailerons, so very hard to get out of it. Link to comment Share on other sites More sharing options...
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