Aviation

If it weren't about the AF447 disaster, some comments of readers in some of the forums were actually funny. Especially those ones writing that Air France just had to install GPS in addition to pitots to indicate the speed of the aircraft when the pitot tubes got unreliable due to icing. After all the el-cheapo navigation system for the car shows the speed quite well. Well, while the speed on the GPS display is pretty precise, it has almost no value for keeping the aircraft in the air.

As you you may from school aircrafts are keep in the air by a force called lift. And aircraft has to create at least enough lift force to neutralize the force of gravity. The lift is dependent on the speed you move the airfoil through the air. Okay, that's vastly simplified but sufficient for my explanation. Dependent on the aircraft design the needed speed to create such an amount of lift is different: For example the Fieseler Fi156 has an incredible low minimum speed: 27 knots. Out of this reason this aircraft is capable to fly backwards in really strong winds. But this backwards flying (negative speed if you want to say so) is just in relation to ground … the airspeed is still positive. The difference between the speed of the wind and the speed of the aircraft have just to be larger than the minimal speed of the aircraft and the wind speed must be larger than the aircraft speed. Don't believe me … just go into the next harbor and look at the gulls. Of course you won't see a Boeing or an Airbus backwards … at least not with usual winds.

Another nice example are aircraft carriers: Those have really large engines to accelerate to and to keep top speed. Out of a reason: When an aircraft carrier moves with 30 knots, the air on the flight deck on the aircraft carrier already moves along the airfoil with 30 knots even on calm day. Let's assume a fresh breeze (6 beaufort) or 30kn. When the carrier steers in the direction with the wind, the air would move along the airfoil … well … not at all. When the carrier goes in the direction against the wind, the air would flow along the airfoil with 60 kn.

That's the reason why an aircraft carrier turns into the direction against the wind to start aircrafts. It gives the aircraft a headstart in order to generate lift. And to get an aircraft to 30kn you need really big engines.

To get back to the difference between airspeed and speed over ground? What's the speed over ground? 30 knots. In all cases. But you have three different air speeds. The GPS only measures the speed over ground. However as mentioned above the lift - the force keeping the aircraft in the air - is dependent of the air speed. At 0 airspeed no lift. At 60 kn a lot of lift. At 30 kn airspeed, something in between. And then you have the jet engines and the catapult.

Speed over ground is something different than air speed. And a GPS can't measure air speed. The air speed can only be measured by measuring the speed of the air flowing along the aircraft. To do so, modern aircrafts use so called pitot tubes in conjunction with measuring equipment to measure the static pressure (the ambient air pressure). The pitot tube measures the ram air pressure into the pitot tube. If there is something blocking the air from pushing into the probe, it can't measure the speed.

So … a GPS receiver would have helped the pilots of AF447 not a bit. There are other means like the Backup Speed Scale but that is working completely different.

According to the Flightblogger, one of the 787 aircraft had to land due to a fire in the electronics bay. It was able to land safely, however a fire and smoke onboard of an aircraft is a very serious incident.

A strange thing is the deployment of the RAT. This is the Ram Air Turbine. An aircraft need a lot of electrical power. This power is generated by the engines, however when all engines have failed, a small propeller is deployed outside the aircraft that is driven by the head wind to provide electical power to the absolute minimally necessary equipment). This generator is called RAT. It's deployed as a last-resort-measure ... so it will be interesting to read in the official incident report about the situation.

An exploded Trent 900 with 0 fatalities gets massive press attention with massive speculation. A crashed ATR-72 in Cuba with 68 fatalities and a crashed Beech 1900 in Karachi with 22 fatalities are just footnotes. Mad world.

Interestingly such uncontained engine failures are as seldom as i thought before searching avherald.com.

Ouch .... this is something you call "uncontained engine failure". This happened to an Qantas A380. TheAustralian has a series of pictures from this incident.

Jet turbines are designed to to keep the debris of the engine in the engine casing. From there the debris stays in the engine or leaves it at the rear end. The engine casing is not the sheet of metal or composites you see from the aircraft window .... this is just the engine fairing for optical and aerodynamic purposes. Anyway: Engine parts punching holes in the wing is a really serious thing.

This looks like an engine problem ... not a problem of the A380 itself. However i expect the media to write, this is a A380 problem. That said it gets interestings here. One of the recent reasons for the delays of the 787 was a uncontained engine failure of the Rolls-Royce Trent 1000. And the Trent 1000 is a derivate of the Trent 900. The Qantas A380 used this kind of engine (you can get two types of engines for the A380: The Trent and the GP7200, an engine made by the Engine Alliance)

It's much to early to speculate about the reasons. This will take a while to find out.

According to avherald.com there was an accident in Riyadh involving a Lufthansa Cargo MD11. Look like an hull loss ... especially when you look at the photos at the end of the article:

Captain and first officer received injuries and were taken to local hospitals. Fire fighters were able to extinguish the fire, that broke out in the center area of the aircraft, front and rear portion were visibly not consumed by the fire.

David Warren died on July 19, 2010 that the age of 85. Why should you care? Well ... this guy created the flight data recoder, better known as "black box". This invention made aviation saver as post-crash analysis is easier with some additional data about the aircraft in the minutes before the crash, thus enabling the investigators to make better suggestions for the future.

The Boeing 787 Dreamliner is already 2,5 years late and the next negative message came in last week ....

Boeing has issued a “caution” that delays in its flight test program may push its first delivery of the 787 into 2011.

I don't think, that this aircraft will lose the moniker "Delayliner" soon.

It's a small change at the Lufthansa Frequent Traveller program and perhaps most people are aware of this change as it was made on 1.1.2010, but Lufthansa changed it back to a "Frequent Traveller" instead of "Most paying" program - at least for 2010. You can get the FTL status with 30 flight legs.

A few weeks ago i wrote about this strange behaviour of airline passenger to storm the aircraft as there would be no reserved seats in it or no kind request to start boarding with the rows in the back of the aircraft.

There is another interesting behaviour: As i'm traveling to the smaller airports with smaller aircrafts quite frequently (Canadair, Embraer or Dash-8 ... not capable to use a gangway), apron-parking is something quite normal for me.

You aren't allowed to walk over the apron, so they use busses to shuttle you to the aircraft. And here the strange behavior starts: No matter how many seats in the bus are still free, everyone tries to stand near the doors. Even when those spaces are overcrowded nobody starts to move into the aisles of the bus except the room is that overcrowded that people are forced to move into the aisle.

I assume airline passengers would still fight to be first in the row or at near as possible to the exists of the bus when 10 passengers are booked for a A380 flight.

A few days ago the A320 celebrated it's 50.000.000 take-off and the five billionth passenger since the introduction of this model in 1988. On the other side there were 9 hull losses with fatalities. So every 5.555.555 take offs there is one crash. If cars would have a crash for every 5 555 555 turns of the key, streets would be a much safer place.

Do your really think, that power cycling your computer is just something people do at home, when their computer acts weird? Well ... not really. In a Safety Alert for Operators issued by the FAAyou will find the following two paragraph:

To alert all operators of MD-11 aircraft equipped with the Honeywell Pegasus FMC, with Future Air Navigation System (FANS) enabled, of possible erroneous Air Traffic Control (ATC) messages displayed in the CPDLC log.

and

On March 11, 2010, Boeing issued Multi Operator Message (MOM) SR1-1536638744. The MOM provides maintenance with procedures to clear the Honeywell FMC ATC Input Buffer by depowering the aircraft or resetting the appropriate circuit breakers before each FANS/CPDLC flight.

There is an issue with the expiration of incoming messages of the air traffic control in the flight management computer. They do not expire after the flight has completeted. So a pilot could take them for current ones and not the ones of the last flight. The current work-around: Power cycling the aircraft or at least the flight management computer

A good example how resilient aircraft engines are: The Avherald published some photos of an engine of an 777 that had to land at Schipol instead of Heathrow because of low fuel. The engine still delivered thrust. It had just a higher exhaust temperature and higher fuel burn according to other reports. At the moment it's believed this damage happened 5 hours before the landing in Schipol

You can call this a fscking large order without exaggeration: Emirates ordered 32 additional A380 today. So far they ordered 58 aircrafts of this type, now their fleet will have 90 in a few years.

Ich mag ja in anderen Blog gerade die Einträge, die Einblick in ein vollständig anderes Berufsleben geben, wenn es sich dann auch noch um die Fliegerei handelt muss ich das einfach lesen. Ich kann da beispielsweise nur sehr den Bericht "Vulkanasche voraus – Umleitung!" im Blog von Guy Gächter empfehlen.