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What makes Airliners So Safe?

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Old 3rd Dec 2011, 12:32
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What makes Airliners So Safe?

Afternoon chaps/chappesses ( depends on where you are )

I'm conducting a little preliminary research for my paper on Avionics pertaining to flight safety improvements over recent years ( its a working title, so deliberately vague and broad) and was seeking a little guidance on specific advances in systems. My initial thoughts related to:
- TCAS
- 'Glass Cockpit; focusing on certain areas/instrumentation'
- Transponder
- GPWS

At this early stage what exactly I want do is not set in stone, however, I don't want to change the focus completely.

I want the paper to give a fairly comprehensive view on the advances and how they have helped contribute to air safety.

Any help would be greatly appreciated;

FS
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Old 3rd Dec 2011, 13:07
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Historical Knowledge of minor system failure rates, multiplicity and redundancy in paths to achieve safe flight with average pilot skill.

Your typical car doesn't have this degree of certified methods

Things that make it less safe

errors in failure rate assumptions (typically not validated) such that multiple failure conditions are likley to occur

Latent failures (no way of knowing that the backup won't work either)

Insufficient pilot knowledge of system
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Old 3rd Dec 2011, 13:34
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Figure out where the advances have come from. I'm guessing CFIT would be #1. Research what created those reductions.

For CFIT reduction I'd credit - FMC's/map display. EGPWS. Training. Recent years GPS can do added to improving FMC/map accuracy.

Obviously technology advance, engineering and manufacturing goes into the advancement of the newer systems/technologies(FMC's, GPS, TCAS, engines, systems design, systems componenets, etc)
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Old 3rd Dec 2011, 13:43
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Longer term safety improvements originated from airframe systems and engine reliably, but here’s not much avionics in those. More recently from avionics system reliability and overall system redundancy – design and certification have helped.
Another aspect has been improved weather information; better communications and weather radar.

EGPWS – note the ‘E’ for enhanced; this has probably had the most dramatic effect in improving safety.

Nowadays there are some improvements from navigation systems, but much of this relates to capability as it does to safety.
Many modern avionics systems are promoted as safety improvements – EFIS, HUD, FMS, FBW, etc, but it may be too early to judge any meaningful results, and there could still be some pitfalls from the rapidly developing capabilities which these systems offer. Also, the industry has to judge (understand) the human interface with these modern systems and any effect on safety. Again, don’t misjudge ‘safety’ for capability – the safety trend is now very flat.

P.S. I would add that most of the safety improvements beyond the development of the equipment relate to the operation of the aircraft; and this perhaps remains the most ‘at risk’ aspect of civil flying.

Last edited by PEI_3721; 3rd Dec 2011 at 14:43.
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Old 3rd Dec 2011, 14:59
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POWER, INSTRUMENTATION, and COMPETITION*.


* For mostly profit reasons, but oh well, safety is safety.

(First World only). The enemies of safety? NATURE. Human and MOTHER.
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Old 3rd Dec 2011, 20:13
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What makes Airliners safe?

mho...

1) The fact that powered aviation will celebrate its 108th birthday in just two weeks.

2) The world is rather large.

3)The viscocity of the air is far lower than water's.

and 4...they really needed to find somewhere to put so many psychopaths(myself included)...and the cockpit of an airplane resulted in a good place.
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Old 4th Dec 2011, 00:55
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What makes Airliners safe?

There's just too much paperwork to do after an accident.
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Old 4th Dec 2011, 00:58
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Ah, EGPWS and TCAS have prevented almost-accidents we will never know about.

And, the avionics and automation in today's state-of-the-air heavy iron (as opposed to commuter birds) is awesome.

The negative is young pilots brought on-line as "children of the magenta line" seem, as a group, to lack basic flying skills when the bad stuff hits the fan. (ala, AF 447, Turkish 737 and Continental turboprop in New York.)
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Old 4th Dec 2011, 01:23
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So ‘the children of the line lack the skills’ (an artifact of using the ‘safety improving’ avionics), or were the children unnecessarily exposed to adverse situations due to ‘failures’ of the avionics (which could have been avoided with the latest standard of modern systems).
Or maybe the high pressure situations which the children had to face were actually of the industry’s making due to commercial pressures or self-inflicted complexities of modern operations?

Modern, safer avionics can have their downside if inappropriately ‘promoted’ as an all-encompassing safety feature, whereas the proposed use of any safety feature must consider the people and the situations which might realistically be encountered.
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Old 4th Dec 2011, 01:53
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The two guys up front, who aren't there unless they are excellent at what they do.
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Old 4th Dec 2011, 02:43
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Put me down for the TCAS and EGPWS, two very good safety-
enhancement tools of trade - they can assist a superior pilot
to avoid situations that require his superior abilities. TCAS is
more a prevention tool, by assisting in situational awareness
as is EGPWS, in avoiding the potential problem before all the
bells and whistles go off).

Glass cockpit when everything is working honky dory? Yeh to
an extent. Same can't be said when everything decides not to
work.
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Old 4th Dec 2011, 05:03
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All those items you mentioned greatly contribute to situational awareness which helps to avoid unplanned contact with the earth or other hard objects. Windshear avoidance systems probably have helped greatly too, but you rarely if ever hear about the "almost happened" events.
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Old 4th Dec 2011, 06:02
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Why so safe?

Two words: safety culture.


In aviation we have a deliberately obsessive interest in EVERYTHING that goes wrong. Every time an avionic device falls over, a pilot suffers a crippling stomach upset, a crack appears where none was expected, a passenger goes off the rails and does something stupid on-board - it gets reported, analysed, and many clever people are involved in determining how to stop that problem either happening again, or if it does, endangering safety.

That is of-course extended to avionics - design, testing and operations.

Of course we get gaps, errors, arrogance, "but we've always done it this way", same as any other community. But the community default is towards safety culture - rather than (say) shipping or road transport where it's more something they do when they've no choice.

G
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Old 4th Dec 2011, 07:42
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---- and an open reporting system with a "no-blame" culture within a company which allows pilots to report errors so that others may learn from them. Not all airlines do this, however.

But, as others have already said, whereas airliners get more "safe", other influences within the industry have cut training to the bone and beyond and written Ops Manuals which all but ban manual flying. One well-known legacy carrier has actually banned the use of manual thrust on its A320 fleet unless it's as a result of an abnormal condition. Not good.

Obsessive use of the automatics has degraded pilot skills without a doubt. Many of the younger generations have not been given the skill in the first place; consequently they lack confidence in their ability to fly manually, in some cases justifiably. They need constant retraining and encouragement in the simulator. The expression "children of the magenta line" (or green line for Airbus) is not a joke. To call many of them "pilots" is stretching the commonly understood meaning of the word. They are button-pushers and some of them can be over-loaded beyond their capacity when asked to fly manually on conventional radio navigation aids in the simulator.

In the UK we now have the MPL. A possessor of this licence can now take the controls of a public transport aircraft with as little as 120 hours in his or her logbook. At a time when the FAA is tightening up on fatigue regulations and licencing requirements post-Colgan, Europe is steering 180 degrees out and it's a serious concern. It is a direct result of too many people in decison-making positions who have little or no experience of the nuts and bolts of aviation; too many generalist managers; too many theorists; too many accountants.

The air, like the sea, is unforgiving of fools and the Swiss cheese holes are lining up.
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Old 4th Dec 2011, 11:03
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It all rather depends on whose airliners you are talking about. Under regimes where the Airline, Airworthiness Authority, and Air Accident Investigator are one and the same to all intents and purposes, ie the Government, then I wouldn't rely on them being "so safe". The reason for when they are "so safe" is that these institutions are separate and independent of each other. Thus an Authority can be found wanting and be criticised by the Air Accident Investigator for example.That is the catalyst for all the technical, training, and reporting initiatives mentioned by other members.
It is of course a contradiction of that happy state of affairs that Military Aviation is usually self regulated and self investigated. You might therefore wonder if military aircraft are "safe", ie are they airworthy? You would be right to do so.
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Old 4th Dec 2011, 12:02
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CFIT always had a much higher incidence than mid-airs, and has reduced sharply since the advent of EGPWS.

So, nice as TCAS is, EGPWS has had the larger positive impact on safety.

Loss of control is now the number one killer, so we either come up with yet another gadget, or start training people to fly again!
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Old 4th Dec 2011, 12:14
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Airborne weather radar without a doubt. Before radar arrived inadvertent penetrations of thunderstorms were the cause of accidents several decades ago. From this came the term "Jet Upset". Just imagine an airliner flying blind at 35,000 ft in areas where huge storms are known to reside and the radar is inoperative. The chances of running into a thunderstorm in some parts of the world including the Pacific Ocean is increased significantly.

Hit one of those monsters and the danger of loss of control is there.
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Old 4th Dec 2011, 14:51
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Just imagine an airliner flying blind at 35,000 ft in areas
where huge storms are known to reside and the radar is
inoperative.
Don't have to imagine it - I know what its like - and at night.
Many yonks ago in a 737-200 when the monochromatic radar
died (not that the damn thing was in any way useful when it
did work).

Occurred twice in my case on 2 different 732s - both during
the SEA wet.
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Old 4th Dec 2011, 22:21
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I want the paper to give a fairly comprehensive view on the advances and how they have helped contribute to air safety.
PROFESSIONAL PILOTS
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Old 5th Dec 2011, 12:54
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Occurred twice in my case on 2 different 732s - both during
the SEA wet.
Snap! Me too in a 737-200 at night out of Taipei for Guam with a typhoon spinning across our planned track 400 miles to east of Taipei. In cloud and swore the radar was picking up reflections from stormy seas but no CB which seemed unusual. Then without warning violent turbulence and usual St Elmo's and all that stuff still in cloud. Checked radar gain and tilt and saw expected flecks from the sea but in fact the radar was inoperative and probably had been so after leaving Taipei. But the screen looked alive.

Resorted to face pinned to windscreen watching for cloud gaps illuminated by between lightning flashes. Then we would weave between tops. Copped it for 10 minutes or so and finally cleared it.

Sorry about the war story...
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