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There is a saying that if one slowly heats a pot of water with a live frog in it the frog will go to sleep and not get out and so get cooked whereas if he is dropped into a hot pot he will leap out. So it is in many situations in life. We have it in aviation where slowly evolving situations get way past a point where some action should be taken because each development is incremental and not so different from the last situation. So it is with Airbus pitots and standby instruments and now with Flight 188 overflying its destination I think we have the same thing. It does not really matter if they went to sleep or lost track of time there was considerable potential for trouble. Much has been made of the poor match of the human physiology and performance and yet steadily the man is being taken out of the loop in flying so that such things can happen. An extraordinary number of RPT flights pass uneventfully but where a trend emerges it should be addressed. Ground control is now possible and studies should be made, discussed and decisions taken. Pilots do not have to leave the cockpit. It is just another logical progression. The Helios tragedy where apparently a cabin crew member was walking about with a portable O2 system but unable to enter the cockpit is another situation where ground control could have saved hundreds. The reasons why this has not happened are many and various and to do with how aviation has evolved a rigid and inflexible regulatory process. Vested interests are many but it is mainly a sort of general inertia and no one has had the courage really to say come on guys wake up or more to the point, hear those who have been saying such. As usual there will be wails of technical difficulty and cost but it seems clear that it is going to be a small cost in the long-term and long over due for considerations. Maybe the risk of different sort of hostile take over is behind the resistance but we seem to find ways to trust our fellow men in many other situations. Why not? Read more…

Recently a student asked me what an open Rotor was and I replied it was basically a turbo prop but with things being how they are a sexier name had to be invented so they came up with this. It got me to thinking; as we are progressively backed up against the wall by reality it is only a matter of time before the open rotor makes its reappearance and so it is timely to have a look at how accurate my glib explanation was. Basically the problem with propellers is that they suffer from severe efficiency losses as the speed of the propeller tips approaches the speed of sound and basically the advantage of them is that they have to accelerate the working fluid (the air they fly in) less because they accelerate a lot more of it. I.e. they have in effect a much greater by-pass ratio than Turbo fans. The big question is where is the best trade off for speed versus efficiency. Time will tell. the Russian Bear long range patrol aircraft with its huge counter rotating props has been with us for years and conferred enormous range advantages when compared with the turbo jets of the time albeit with a considerable disadvantage in reliability. The new A400 European Military lifter will set new standards of frugality and is forecast to cruise at 450 kts which is quite respectable. After the next round of geared fans it looks as it there is only one place to go and that is the Open Rotor. Look for it in the next new wave; maybe with a blended body conformation aircraft. Read more…

Here at the AN we do not know what causes accidents, or even death for that matter. We leave that to the experts. It does appear that victims advised by their lawyers have ventured there, and now read this:
You may need a web page translator to render French to English.

AF447: The crash of Paris-Rio was avoidable

The Union of Airfrance Pilots(SPAF) say in this report, it is the failure of the Pitot probes to measure speed that caused the crash.

Suddenly AF447 is back in the limelight. This will not go away, lawyers are on the case. The Black Box will probably not be found, but if it were ever to be found many anticipate it would simply elucidate the sequence. At some point the ADIRU gave up resulting in a handover to the pilots in impossible conditions.

Nobody knows exactly what happened to AF447 but what we do know is that airspeed measurement is of critical importance when we are flying at great altitude in subsonic airframes. In pilot slang, as you ascend you enter the coffin corner, the apex of which is a point where the aircraft is stalled and exceeding the speed of sound (MACH 1)
simultaneously, hence the name.

Here is a simplified graphic of coffin corner courtesy of Wikipedia. With increasing altitude the stall speed increases and the speed of sound decreases. Our long distance RPT jets spend a large percentage of their flight times in the vicinity of this no go point. The fact that jet travel is very safe is testament to the skills of the engineers, scientists and pilots who make all this viable.

Those of us that fly are well familiar with the airspeed pitot system, in fact most of us can tell a story about what went wrong. Insects, dust, ice, covers left on, paint, masking tape, and so on. There have been major RPT catastrophies outside of the coffin corner for these simple reasons. Shit happens, we all know that. The difference with coffin corner is that we are high and fast, a long way from home with poor or no visual reference, and in addition we are stalling or breaking up, all mediated and filtered by a computer which says over to you.

In the great Echo-Chamber of the Internet you will read that we are depending upon the 18th. century technology of Henri Pitot to measure airspeed. In fact there has been a steady development from the time of Darcy in the 19th. century until now. We are committed to subsonic flight for long range RPT, but this pneumatic sensor technology may have hit it’s use by date.

In the very early days the pioneers flew without air speed instruments. The Wrights used a crude angle of attack indicator, Bleriot flew the English Channel with no airspeed instrument. The onset of WW1 encouraged the development of the Pitot-Darcy pitot method of differential air pressure devices to measure air speed in support of the fast and high powered aircraft required to fight a war. The highly developed devices in use today are direct descendents. Essentially they tap ambient air using pitot probes and static ports, measure the pressure difference, then compute and display a calibrated airspeed.

Airspeed measurement technology is in the headlines now, for everybody, not just the aviation buffs.

YIKES!!. What a coup for photographer Stefan Sonnenberg. You can find him here…http://www.airliners.net/aviation-forums/profile.main?username=Whisperjet

Germania Boeing 737-300  registration D-ADII flight ST-8656The starlings had a bad day, as well as Germinia who have to fix the engines.

It was a lovely VFR day and the pilots did it well as a procedural engine fail on takeoff. Hopefully Stefan will get an award for his image, he certainly deserves that. In the event the aircraft returned to Dusseldorf with no problems other than those for the passengers to explain their late arrival. More here http://www.dailymail.co.uk/news/worldnews/article-1217035/Bird-strike-The-moment-200-starlings-sucked-passenger-jet-engine-off.html

Getting back to aviation, think about what would have been the situation if some of the unfortunate birds had shut down the pitots as well, clearly visible in Stefans pic. Under the VFR conditions applicable the pilots would have done just as well, except that they would have been challenged a little. If however they were entering turbulent IMC they would be challenged greatly. Such is the importance of airspeed in aircraft operation.

More on this in a later post. Hope you liked the pic.

Some time ago there was a flurry of interest in the blended body concept in which the wing and body of an aircraft are blended as a way of minimising drag and as a result maximising efficiency.
The concept is not new and there have been a number of pioneers who attempted to develop and put into service an aircraft which could take advantage of the theoretical gains available.
The Horten brothers in Germany designed and flew a number of flying wings aircraft but the end of WW II brought this program to a halt before it could be developed. Another concept which has also been seen to have promise is the lifting fuselage proposed by an American pioneer Burnelli who designed built and flew a lifting body aircraft. In addition to the reduction in drag postulated they had advantages of being crash worhty and having large cabin volumes. There were not surprisingly, problems of various sorts. Flying wings for instance were difficult to fly being unstable.The problems were never adequately solved until modern capabilities made the management of them possible and as a result conventional strategies have been progressively developed and given rise to the airliner as we know it. A long fragile pencil with thin and structurally demanding wings.
Some manufactures have talked of these advantages and have proposed and done detailed planning. One of them being Boeing. The advantages never seemed to outweigh the risks. Not the least of the problems might have been how unconventional they would look to eyes used to the current form. Money talks, however and the environmnt may soon be screaming.
The tide may be turning with a number of manufactures now talking of the blended body as having significant attraction as consumption of oil and production of CO2 become increasingly a problem. Engine and airframe development and aerodynamic refinement are reaching a point of diminishing returns with curent formats and to make further gains more radical solutions will be have to be explored.
It has been claimed that the Blended body, which combines the virtues of the flying wing and the lifting fuselage, used in conjunction with advanced engines such as the open rotor, may be as much as 25% lower in fuel burn compared with the best contemporary practice. Read more…

Finally the capability to use mobile telephones is being offered by an increasing number of airlines. We, the passengers have been clamouring for this for years in despair. This was a fight with too many dogs.  National aviation and communication regulatory authorities,  Industry  governing bodies,  manufacturers, air crew associations, telecommunications providers, you name it, and of course us, the customers. Eventually an acceptable model emerged for the enabling technology to go forward.

Each aircraft is equipped with a picocell. This is a low power cell phone tower operating within the cabin . This interfaces with the on board satellite communications links to interoperate with  the terrestrial  telecommunications networks and so process the call normally with full functionality.  That is actually very elegant and many enhancements are in the works for Wi-Fi internet access for example raising issues about VOIP and firewalls and the rest of it.
The main providers at the moment are OnAir (http://www.onair.aero) and AeroMobile (http://www.aeromobile.net). The rush is on….

Read more…

On Oct. 1, 1969, the Concorde 001, a joint British-French venture, traveled faster than the speed of sound for the very first time. It was the aircraft’s 45th test flight and it held Mach 1.05 for 9 minutes at 36,000 feet and 75 miles from Toulouse, France.

It wasn’t the first commercial aircraft to break the sound barrier, that was the Russian Tu 144 which had beaten the Concord by a few months but it was the Concord which went on to provide many years of commercial supersonic passenger flight.

Supersonic flight was for long only a dream but in 1974 Chuck Yeager (whom I have shaken hands with and is a real man who likes hunt’n shoot’n n Fish’n) was credited with being the first man to fly faster than sound.

For many years supersonic flight was the realm of the military only but Concord changed all that.

Although Concord has now been retired as uneconomic it looks likely that either as a luxury for the very rich or a service for corporated princes Supersonic flight will soon return to civil aviation as more and more projects move to fruition. In the mean time we will have to leave it to the military to provide us with sights such as this F 22 with its striking cloud trail.
The phenomenon is called a vapor cone or a shock collar, and, if you want to get really technical, a Prandtl–Glauert singularity. It is beautiful demonstration of how quickly things happen at the molecular level

Read more…

It had to happen and now we see the first move along the feeding chain of aviation litigation for the AF 447 tragedy.

lawyers want EUR1 billion as a starting point for AF447 – victims

The Air France crash on June 1 was the result of a preventable mix of human and technical failures, according to Stewarts Law, a UK law firm representing 50 of the victims’ families

Stewarts Law presented arguments in Paris this week after experts used a simulator to replicate the conditions experienced by the crew of the Airbus A330 in a storm off the coast of Brazil.

The firm wants Air France and Airbus to put the EUR1 billion into a pot to be divided among the families.
Read more…

It was inevitable that there would be an engine incident in the A 380. Yesterday a Singapore airlines flight from France to Asia was returned to Paris after an engine warning lead to one of its four RR Trent 900 engines being shut down. The engine will be changed and the passengers put up in Hotels overnight. The Trent was the launch engine for the A380 and at present 52% of the A380 orders carry the RR engine. The other option is the GE, P&W Engine Alliance GP7000. The RR Trent 900 developed from an earlier version of the highly reliable Trent 500 has a number of advance features including light weight wide chord swept fan blades and Hamilton Sundstrand Fuel controllers.

Given there are four engines on each aircraft and the operators have been doing their best to fly the pants of them it is no surprise that there has been an in flight shut down and in fact one could even say it has been an eagerly awaited event for the voyeurs and pundits of aviation not to mention the industry in general. Read more…

Randy Tinseth, vice president for marketing at Boeing’s commercial aircraft unit wrote in a blog post that workers at Boeing in Everett, Washington, have begun fixing a flaw on the first 787 Dreamliner test aircraft in preparation for its long-delayed first flight later this year.
Modifications to reinforce the areas where the plane’s wings join its body had recently begun, three months after the company again abruptly postponed the Dreamliner’s long-awaited test-flight program. Read more…