Monday, January 19, 2009

Safety Is Not a Miracle

A few days ago, a US Airways A320 airplane took off from La Guardia, New York and flew through what is suspected to have been a gaggle of geese. Airplane engines are designed to withstand ingestion of small birds, but that is no guarantee. A jet engine requires a precise flow of air controlled by multiple banks of meticulously shaped fanblades, and when those blades are mangled and clogged by the impact of flesh and bones, it is quite possible for the resulting cascade of shrapnel to overwhelm the engine. Or engines, as appears to be the case, the pilot having radioed the control tower about a "double bird strike."

As everyone in the television-watching or newspaper-reading world is aware, the captain ditched the airplane in the Hudson River and all passengers were quickly evacuated before the fuselage submerged, with no loss of life. And then, having interviewed everyone available and panned around everyone's cellphone photographs, for lack of anything else to say about it, the networks and headline writers started calling it 'a miracle,' and making me yell at the TV. Don't get me wrong: this landing wasn't a routine occurrence. It's a stunning, inspiring event. It's good that no one died. It's also good that no one died on the hundreds of flights US Airways conducted that day without incident. But I think it's somewhat insulting to attribute any of that safe flying to divine intervention.

People set standards for training, materials and procedures and people designed and built and maintained that airplane while other people trained and practiced and did their jobs well. Standard operating procedures are a system of a thousand things that are done every day, in a particular way, even when they are annoying, or boring or time-consuming. Pilots practise the required procedures for engine failure after takeoff. We practise in simulators and/or during training sessions in the actual aircraft at altitude, depending on the aircraft and the company. We recite the procedures aloud in our pre-takeoff briefings and practise them in our heads. I suspect that many pilots who regularly fly out of La Guardia have mentally ditched in the Hudson River many times. It appears to be the best clear path for an aircraft that can manage neither to return to La Guardia nor make the runway at Teterboro.

I don't know how many times I've heard people mock the water landing page on the folding safety briefing card, disbelieving that a commercial airliner could be landed on water and sit there floating like the picture. Up to now I've been citing the B727 B707 that landed on Lake Victoria by accident. In that case the airplane touched down with gear extended, because the airplane was too low on the glideslope for the intended airport. The gear sheared off, the engines on the wings sheared off--as they are designed to do--and the airplane came to rest right side up and floated until the next morning. I understand that the engines sheared off the A320 too: the last I read they were still looking for them in the river, in order to investigate the accident and get the DNA of the guilty birds.

Dave estimates that not more than a dozen line pilots could have kept their cool and landed an airplane on the river that well. I shouldn't question his experience, but every line pilot knows the drilled emergency procedures and has practice every-single-flight in touching down perfectly straight, wings level at the prescribed speed, every single time. Given that place and time and the placid river, I think many could have done it. I don't envy Sullenberger the chance to try, though. A lot of things had to go right for that to work as it did.

The incident inspires me to greater professionalism, to know my emergency procedures more fluently, to mentally practise what could go wrong everywhere I work, to make every routine landing as perfect as possible and to ensure my passengers are thoroughly briefed and understand the importance of following them. I'm sure more passengers will pay attention to the safety instructions before departure now, enough that I need a at-shirt now, saying "I paid attention to the passenger briefing before it was cool.

Curiously, it seems that most people exited onto the wings in this case, but the United Airlines A320 safety briefing (I couldn't find one for US Airways) advises passengers not to use the overwing exits in the case of a water landing. I would expect the instructions to come from Airbus and that US Airways would give similar directions, but then not all the passengers obeyed the instructions that were given. One article mentions a woman who tried to retrieve her cabin baggage from the overhead bin. When told to leave it she insisted that she needed her stuff. A man interviewed on CNN was proud of trying to evacuate "women and children first," but I'm suspecting that in the confined space of an airplane cabin any kind of precedence wasted time needed to get everyone off the airplane. Likewise at least one evacuated passenger re-entered the aircraft from the wing in order to reach a different raft. Puzzlingly, this article states that the captain refused a lifejacket, as though it was somehow a heroic gesture. What the hell? I find it hard to believe that that refused a basic safety device in order to look bold and captainly on the news. I understand that he was searching the cabin to make sure there was no one left behind, and possibly anticipated having to dive down to escape if the airplane changed orientation while it sank, but why not wear the thing as an example, and just not inflate it.

There have been two air incidents in the last month, both engine failures at take-off, that could have been tragedies but had one hundred per cent survival. The system is working, but investigators will still comb the wreckage for ways to improve procedures, facilities and aircraft in order to increase safety for future flights.


Anonymous said...

I thought it was odd too that passengers were on the wings. I don't have time to search the FAR/AIM for recommended safety and evacuation procedures for a water landing at the moment, but I had always assumed avoiding the window exit had to do with two things.
1) no raft. Unless you're flying an aircraft that has doors for "over-wing" exits, and thus, has a slide/raft, popping the windows servers no purpose, as the idea is to get everyone onto a raft with an ELT.
2) In the same situation, you avoid filling the aircraft with water.

I think evacuation procedures were crafted to be most useful crashing in the atlantic or pacific, not the hudson. Many mocked the water landing portion for trans-cons because nobody could conceive of anyplace between the coasts (US) that would actually require a water landing.

Additionally, non-ETOPS aircraft slides are designed mainly as slides. The two slides that deployed from the front doors weren't going to hold all the passengers, and, in the panic, the over-wing exit passengers simply wanted OUT NOW.

As it happens, standing on the wing probably staved off some bad hypothermia cases, letting passengers keep they're heads out of the freezing water, and have quicker access to the ferries that came to the rescue.

Scoon said...

If a journalist writes a story with no superlatives, does anybody read it?

Remember: these are the same people who describe sports teams winning by one point/run/goal as a 'miracle'.

I also laughed when one witness actually took the time to mention to a reporter that the landing gear wasn't down!

Because... you know... maybe that's why the plane sunk. Too bad Jesus wasn't on board ;)

Dave Starr said...

Well I do believe there is a skill knowledge test required for appointment at major networks which denies emplyment to any college graduate who understands any demonstrable principle of aeronautics. They seem to provide the proof of this theory on a daily basis whenever anything with wings is remotely involved.

But I've been searching the 'net in vain for pictures of the B727 that lost its wing mounted engines ... ;-)

Ed said...

Yep, B707.

Aviatrix said...

the B727 that lost its wing mounted engines

Heh, I could work for a news network!

Sarah said...

Aw, you could totally write for a newspaper. The NyTimes still has an article up describing a 737 birdstrike incident where "smoke and the smell of burning feathers ... came from the rear engines".

No miracle, but it must have been quite an experience. I admit I fired up X-Plane ( hey, it's for approach procedure practice, I'm not playing airline pilot - no uniform or _anything_ ) and did some take-offs from r/w 4 at KLGA. I tried 3 ways, and neither airport worked, the only way out was the ditch.

Things happened fast. One of the more interesting posts I saw was a 738 "ditching" checklist. If the A320 is similar, the crew was really really busy. It was 4 pages long! The first 2 items silenced the aural alarms. Who wants to hear all that noise during the critical touchdown?

I don't begrudge Cap'n Sullenburger and the crew their 15 minutes of fame. They definitely earned it.

nec Timide said...

Any of the private pilots out there who ever have the opportunity to to fly with a commercial pilot with lots of time in a multi-pilot crew environment should do what ever it takes to make it happen. And make sure the commercial pilot takes the controls. I had such an opportunity not long ago, the ease with which she wrapped me up in two pilot CRM was a joy to experience. The information exchange rate was very high, never stressful. A completely different experience than having an instructor in the right seat.

Because of that I know it is not remarkable that this crew was able to assess the situation and bring about a successful forced approach in just over 3 minutes, but the predicable result of a great deal of experience, training, and learning from past events.

You are so right Aviatrix, safety is not a miracle, it is the result of a lot of hard work, dedication and professionalism.

nec Timide said...

AVWeb has what looks like security camera footage of the ditching. Unfortunately the sound track is also playing up the miracle aspect. But, if you keep the volume turned down you can watch what looks like a very pretty landing.

dave said...

I printed this post ("Safety is not a Miracle")so that I could read it carefully before commenting. Having said that, this comment is only my opinion and you know what opinions are like...

I stand by my "guess" that only very few line pilots could pull this off successfully for the following reasons:

1- We do not practice dual engine flame outs at low altitude because they are unrecoverable and most likely unsurvivable. After the sim training is over and if there is any time remaining the sim instructor might ask if there is anything you would like to try for fun, like flying throught the arch at STL, rolling the aircraft, or a dual engine flame out. I have successfully restarted an engine after a dual engine flame-out at 5,000 feet, I think. Just barely... Probably could not have done it on the line, though.

2- A heavy airliner can glide, sort of... It is more like riding an iron rail down to the surface at, best case scenario, 1600 fpm. That figure comes from my Pilot Operating Manual for the A320. Then, of course, the no-engine flare would have to be done perfectly or you would run out of energy quickly which would lead to disastrous results. These air frames are heavy.

3- I believe they hit the geese at 3200 feet AGL. Captain Sully had to get the nose down quickly because they were probably very close to best glide speed at that altitude. In front of the aircraft were two gateways; one to eternity and the other to life. I think most pilots, including myself, would have turned toward a runway which could not have been reached. His instincts gave everyone life.

This Captain (with a capital C) pulled off one of the most amazing feats of airmanship I have ever seen, read of, or heard about. I think it was miraculous. I can only look up to the high ground where this guy now resides.

Aviatrix said...

Thanks for the follow-up, Dave.

It's notable that you highlight the skill in decision-making--the decision to land on the river--over the mechanical skill of keeping the wings level, the speed exact and the flare height perfect.

My thinking was that after deciding to land on the river many skilled pilots could have done it, but I hadn't stopped to wonder how many would dare do something that audacious, when two airports beckoned, almost close enough.

Lord Hutton said...

Congrats all round for avoiding the built up area in what was basically a glider, but heavier. A real life happy story that needs no spin to make it better

Anonymous said...

A cousin who now manages pilots instead of being one described a no-power Airbus landing: the pilot controlled the aircraft with just the engines, like steering a hang-glider. The landing did "considerable damage to the aircraft" but didn't kill anyone.
Afterwards they tried it in a simulator and none of them could do it.
Maybe the kind of person you want as an airline pilot is the one who flies their socks off when there's no other way out?

nec Timide said...

I really appreciate Dave's insight into this from a line pilot point of view, and don't disagree with anything he has said except that it was miraculous. But since I share one qualification (glider pilot) with Capt Sullenberger I think I can shed some light on some of the decision process. Not to take anything away from his demonstration of superior airmanship, just my thoughts of where he might have come up with some small, but key aspects.

1. Landing off field is something that all glider pilots must come to terms with and be ready to experience every time they take off. I know of some soaring clubs that won't allow a pilot to go solo until s/he has demonstrated a successful off field landing. Bush, float and helicopter pilots probably also share the mind set that this develops that allows one to move through the realization that no runways are reachable, it isn't the end of the world, get on with picking the best available spot that is within reach.

2) Once you know the best glide or in glider parlance best lift vs drag or L/D speed for a given weight (and configuration), flown at that speed an airframe will always attain the same glide angle (for that configuration). So glide performance is something that can be reliably estimated. The high sink rate just means it's over faster but from what Paul says, this is roughly equivalent to a glider rope break at about 300 ft AGL.

3) Low altitude power loss, through premature release or rope breaks, is something glider pilots deal with on a routine basis. Proper pitch control immediately following a rope break is critical to a happy outcome, as Paul suggests was necessary here. Regular practice of recovery from a premature release at altitudes as low as 300 ft AGL is routine.

I'm not saying that any glider pilot could do the same thing in an Airbus, but the experience and skills developed in airplanes without engines was doubtless a useful addition to Capt Sullenberger's professional abilities.

I think this crew when faced with what Paul describes as unsurvivable, determined that together (and I'm including the cabin crew) they had the skills to give their passengers the best chance to survive. There are lots of aviation accidents where all ability of the crew to act is taken away from them. But in cases like this, where the crew has something to work with, and pulls of a perfect outcome I think they deserve full credit for a job well done.

Blondie said...

It's just our job!

Upside-Down Twizzler said...

I am sorry but I disagree with you.
You can train train train all you want but that doesn't mean you will rise to the occasion and not panic.
I got myself into a bad situation that could have ended horribly, but it didn't because of my training and quick thinking. I know other pilots more experienced then I who have wrote off airplanes in the same situation.

Just because you train for ditching doesn't mean you can do it for real. Just like training for ifr is not the same then actual ifr.

Flying Europe said...

Hi Aviatrix,

I like your post. Well written. I do agree with Dave though. You can have all the training and SOP's you want, this scenario is "not supposed" to happen so it just isn't trained. If it were, there would be no airplanes with "only" two easily destroyable engines...

And with all due respect for the glider pilots of this world, Captain (with a capital C) Sullenbergers gliding experience was most probably not a major factor in the successful outcome of this scenario.

If he walked the empty plane once or twice or if he wore a life vest or not is of no importance.

He's a darn good pilot of the "old creed" that knew how to fly his airbus, pointed towards the river and landed. All on board survived. The rest is history...


majroj said...

The last seconds of the "approach" on the video are "sweet", attitude/timing versus rate of descent and groundspeed (waterspeed?). I wonder how much "ground effect" played into those critical moments?

Training gave them the tools, but temperment allows you to use them.

Aviatrix said...

Great article in the Gazette about it being professionalism not heroics.

Kris Johnson said...

Nice article about how seriously that captain takes safety:

nec Timide said...

More evidence (you may have already seen) from NTSB (via AVWeb) that the ability to parlez a successful outcome from a total loss of thrust is not uncommon.