As I suspected, the new focus on airline safety is all about bird strikes.  The Middle Seat Terminal Blog (a Wall Street Journal blog) has THIS post.  After the US Airways Flight 1549 ditching, I suspected that there would be lots of chatter about preventing bird strikes and there has been.

 

Some of this chatter is about putting screens in front of the engines, for instance.  No one stops to think just how strong and well engineered a screen would have to be to withstand the force of an 8 pound bird and well as how fine it would have to be to keep debris from entering the engine.  Nor does anyone consider that by putting such a screen in front of an engine, you are effectively disrupting the air flow into the engine and that will, at the least, reduce engine efficiency if not keep it from operating as designed.

 

Consider a goose that weighs about 4 kilograms being struck by an aircraft going about 250mph.  That is just about the exact scenario for Flight 1549.  Such an impact represents over 27,000 joules of energy.   In very rough terms, that is enough energy to move more than 3 tons of weight about 1 yard.  By the time you engineer a screen for that jet engine, you need a better, more powerful jet engine to carry all that extra weight. 

 

The truth is that bird strikes are not uncommon and almost always result in non-event.  In fact, engines and other parts of aircraft structure have to be engineered to withstand most bird strikes likely to be encountered.  Jet engine makers have to prove their engine can take a strike and not furiously disassemble itself and damage a wing or fuselage.  Cockpit windows have to be able to take a punch too. 

 

The truth is that commercial aircraft handle these events very well and what happened to that Airbus A320 was actually a statistical anomaly.  It is so rare for a commercial jet to encounter birds and lose both engines to the point that the aircraft cannot return to an airport that in my research, I cannot find another instance.  Oh, it may well have happened but it is exceedingly rare. 

 

Put another way, you have a far greater likelihood of experiencing an “incident” from turbulence than you do from a bird strike.  That doesn’t keep you from flying does it?   From my perspective, this incident proves that nothing more does need to be done to mitigate problems from bird strikes. 

 

First, it is rare for them to disable an engine but it does happen.  A jetBlue Airbus encountered a bird strike this past weekend and rejected its take off.  After returning to the terminal, evidence of a bird strike was found.  Any other week, this would not have made national news.  For birds to disable both engines is virtually unheard of and that is a good thing.  Any modern two-engine airliner is capable of taking off, losing an engine and maintaining climb power to go around and return to an airport. 

 

Airports do their part to prevent this problem.  Unfortunately, airports happen to be places that attract birds because of the wide, open areas that are flat and which generally contain a lot of what birds want.  Airports scare them away and do their best to make flight areas a very unattractive place for them to flock to.  And they are very successful at that in general. 

 

One of the other points that I think escapes what happened to US Airways is the altitude that they encountered these birds at.  It was at about 3000′ above the ground and how common do you think it is to find birds at that altitude?  Very rare.

 

The traveling public is quite safe when it comes to bird strikes.  This was an anomaly and you are just only now hearing about this “problem” because it just rarely happens to ever truly affect a flight. 

Filed under: Airline News, Airports, Trivia by ajax