Which redundancy?

[Eric Janson]

[quote author=Colonel Sanders link=topic=2315.msg7172#msg7172 date=1457292170]

Even worse: with all the required redundancy and
backup in the cockpit, you inevitably end up with an
incredibly complicated system that really no one
understands.

Everyone shits on the Asiana 214 crew that took out
the seawall at SFO, but the guy flying it honestly
thought he had auto-throttles - but he didn't because
of the incredible software complexity.  Do some research.
[/quote]

I'll agree that modern jets are extremely complicated and system integration isn't transparent. It doesn't help that the manufacturers only gives you limited information about these systems. The philosophy is to give you only enough information to operate the aircraft safely.

With regard to the autothrottle system both Boeing and airbus [b]clearly state[/b] that if the system is not performing adequately it has to be turned off and thrust should be set manually.

Autothrottle mode is clearly annunciated in the top left corner of the PFD (Primary Flight Display). For landing the system must be showing it is in a "Speed" mode. Anything else means something is wrong. When I flew Boeings it was "Manual flight - Manual Thrust". The only time I landed with autothrottle was on a Cat2/3 approach.

I guess times have changed.

Asiana 214
[url=http://www.ntsb.gov/news/events/Pages/2 ... tract.aspx]
http://www.ntsb.gov/news/events/Pages/2 ... tract.aspx[/url]

[quote]
The flight was vectored for a visual approach to runway 28L and intercepted the final approach course about 14 nautical miles (nm) from the threshold at an altitude slightly above the desired 3° glidepath. This set the flight crew up for a straight-in visual approach; however, after the flight crew accepted an air traffic control instruction to maintain 180 knots to 5 nm from the runway, the flight crew mismanaged the airplane’s descent, which resulted in the airplane being well above the desired 3° glidepath when it reached the 5 nm point. The flight crew’s difficulty in managing the airplane’s descent continued as the approach continued. In an attempt to increase the airplane’s descent rate and capture the desired glidepath, the pilot flying (PF) selected an autopilot (A/P) mode (flight level change speed [FLCH SPD]) that instead resulted in the autoflight system initiating a climb because the airplane was below the selected altitude. The PF disconnected the A/P and moved the thrust levers to idle, which caused the autothrottle (A/T) to change to the HOLD mode, a mode in which the A/T does not control airspeed. The PF then pitched the airplane down and increased the descent rate. Neither the PF, the pilot monitoring (PM), nor the observer noted the change in A/T mode to HOLD.  As the airplane reached 500 ft above airport elevation, the point at which Asiana’s procedures dictated that the approach must be stabilized, the precision approach path indicator (PAPI) would have shown the flight crew that the airplane was slightly above the desired glidepath. Also, the airspeed, which had been decreasing rapidly, had just reached the proper approach speed of 137 knots. However, the thrust levers were still at idle, and the descent rate was about 1,200 ft per minute, well above the descent rate of about 700 fpm needed to maintain the desired glidepath; these were two indications that the approach was not stabilized. Based on these two indications, the flight crew should have determined that the approach was unstabilized and initiated a go-around, but they did not do so. As the approach continued, it became increasingly unstabilized as the airplane descended below the desired glidepath; the PAPI displayed three and then four red lights, indicating the continuing descent below the glidepath. The decreasing trend in airspeed continued, and about 200 ft, the flight crew became aware of the low airspeed and low path conditions but did not initiate a go-around until the airplane was below 100 ft, at which point the airplane did not have the performance capability to accomplish a go-around. The flight crew’s insufficient monitoring of airspeed indications during the approach resulted from expectancy, increased workload, fatigue, and automation reliance.[/quote]

I can still remember Asiana trying to shift the blame onto Boeing when their own crew didn't follow company procedures. Disgraceful.

The Primary task of the Pilot Flying is to [b]fly the aircraft[/b] and ensure that all parameters remain within the correct limits.

The Primary task of the Pilot Not Flying is to [b]monitor the aircraft flight path[/b] and call any deviations.

Neither of the above happened or this crash wouldn't have happened.

[Liquid Charlie]

My answer -- neither cabin class piston twins and single engine turbines should not be licensed commercial IFR--

[Colonel]

This is a repost of a repost of a repost, but:


[youtube][/youtube]


"Three levels of automation"

Too bad the guy flying Asiana 214 couldn't have
spent a few minutes and watched this.

[Liquid Charlie]

Colonel - Great video and at about minute 15 is what is really applicable to some of the mindset here, especially when I see so many comments on the need for an autopilot. While I have not seen this particular video I have been in a number of those lectures on the problems of automation and the impact on stick and rudder skills and the dependency on automation.

Back to the original question. What people choose to fly for personal use is obviously their own choice. Personally I feel safer in a cabin class twin, single pilot IFR than I would in a single engine turbine. That is to say as long as I was flying I would take my kids with me. The majority of my engine failures/shutdowns have been turbine and jet engines. The argument that turbine engines don't fail is as stupid as it gets. The chance that both piston engines fail at the same time is very remote and likely if they did it was because on one's own stupidity.

The reason I'm opposed to these aircraft commercially is simple. When I jump in my cabin class twin I know it will fly on one engine because I will be well under gross. Commercial operators certainly don't want to operate that way and will always be in the red zone when trying to make money. As for the PC12's etc I got too much Brit in me. I still prefer "multi" engine aircraft before twins  ;D

Oh ya - what's all this hype about single pilot IFR - I preferred it when I flew light twins - if you use the argument 2 pilots are safer, then we should never have removed flight engineers from "big" aircraft. 

[HiFlyChick]

Regarding the question of turbine single or multi piston, I'd have to revert to the old saying "All your eggs in one basket".  Now it might be a really nice basket - heck it might be a top of the line steel basket, but it's still only [u]one basket[/u].  And there's another old saying, which absolutely drives me crazy, "The second engine just takes you to the scene of the accident..."  Stupid!  And right up there with the saying, "There are two types of retractable gear pilots, those that have had a gear up landing and those that have not yet had a gear up landing."  It's been my experience that people that make statements like these have either (a) never flown the type in question or (b) have flown the type in question and screwed up.  I'm not saying that in an emergency situation it's not easy to get behind the aircraft and make mistakes, but that's what training is for.

To revert to the old basket example, I agree that two baskets are not better than one if when one basket fails you take all of your eggs out of the good basket and throw them into the broken basket, or if you scream, throw both baskets up in the air, and run around in circles underneath your falling eggs.