Airplanes

[DC_P]

The autopilot isn’t really all that different from the one introduced with the NG 20 years ago. The model? Not sure. It’s only 2 axis tho. Yes. Two axis. It doesn’t trim rudder. So on an autoland you must disconnect the autopilot immediately upon touchdown and fly it manually thru the rollout. The only way it qualifies for CAT III is because of the HUD. It provides the additional rollout cues to satisfy the feds.

Not to contradict you (because you seem to be way more knowledgeable than me) but I don't think the HUD is what makes it CAT3 capable. Some airlines can do CAT3 to 50' using autoland on the 737 ('monitor AIII' is recommended), and the MD88 was the same. When I first switched from the 75 to the 88 I was surprised to find out the autoland crosswind restriction was based on landing in a crab...

It gets back to the original Type Certification and Herb Kelleher. He didn’t want added technology that would have forced new type certification. So...in the quest to make their primary customer happy, they shit canned the entire 757 program, destroyed all the tooling and jigs, and hung their hats on a design dated from the late sixties.

Depressing every time I think about it. I am going to bid back to the 757 later this year. Still the best airplane I have ever flown.

[entropy]

I think we’re both barking the same tune, just not realizing it.

I’ve always understood that CAT3A required (like you stated) a decision height not less than 50’ with the ability to visually rollout after landing. The HUD, because it gives you steering guidance (via the expanded localizer tracking cue) allows for slightly lower RVR minimus than what is allowed without the HUD. (It’s only a few hundred feet IIRC.) This is something that is applied for and granted via the individual operators OpsSpecs similar to other exemptions like 3585 etc. CAT3B (and CAT3C) do not have a “Decision Height” but rather an “Alert Height”, and do not require manual rollout. It’s referred to as “Alert Height” because while you DO need reported RVR minimus, *cough 😁* you DO NOT need to see the runway physically like CAT3A. In addition, CAT3B and CAT3C require the entire autopilot system to be “Fail Operational”. In other words, one of the three independent systems can fail at the most critical point (inside 50’agl but don’t quote me) and the aircraft will land with no deviations. CAT3A only requires the system to be “Fail Passive” with the requirement that it touches down within the confines of the runway.

This “Fail Operational” vs “Fail Passive” is the heart of all this. The 737 is NOT “Fail Operational” and can never be. The systems (particularly the electrical system) was not designed with the redundancy required to meet this requirement. While it goes thru the “dance” of bus splitting and isolation, there isn’t a “third independent monitor” if you will. That “third monitor” is the third autopilot in the 757/767, or in the case of the Airbus, the separate independent flight control computers which monitor and control...well...just about everything. I’ll raise my hand right here and say that I have ZERO clue on how all that works and was approved on the Airbus...waaay above my level of understanding. For those non-pilot/non geeks here, you just can’t go and “add” or “change” a certified aircraft. It’s certified as being designed/built a certain way. Change it too much...and it’s something different. In modern terms, a 737 cannot “self identify” as a 787. 🤪

I never graduated Mad Dog school beyond the -30 so not sure how they were set up. The 727s I flew were only CAT2 capable. I certainly agree on your opinion of the 75 tho...what a gentleman’s aeroplane. I’m jealous. Not sure if you ever flew the Bus, but I always thought it to be the “nerdy introverted cousin” of the 757. While I never flew it, I always wanted to fly the 767ER. The times I jump seated on it, it was like riding in a 70s caddy...smoooooth. Any chop or turbulence would literally rock me to sleep.

*edit to add*

Sitting here with my morning coffee, I’m trying to set my “wayback machine” to the year 2000. On the 757, when you selected the third autopilot, there was an indication on the PFD at the top center. What did it say again? Did it say “CAT3” in green? Crap...help me out! It’s driving me nuts! Old books sitting in storage locker currently...lol

[Kanye Wyoming]

[GJM]

https://www.wsj.com/business/airline...pirit-18f7e233

This Has Been Going on for Years.’ Inside Boeing’s Manufacturing Mess.
Outsourcing worried engineers and sparked battles over quality before a door plug blew out on an Alaska Airlines plane midflight

The site of this month’s midair door-plug blowout on this Boeing 737 MAX 9 is behind the wing, outlined in red.
The site of this month’s midair door-plug blowout on this Boeing 737 MAX 9 is behind the wing, outlined in red. MATHIEU LEWIS-ROLLAND/GETTY IMAGES
By Sharon TerlepFollow
and Andrew TangelFollow
Jan. 13, 2024 at 12:01 am ET

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Long before the harrowing Alaska Airlines blowout on Jan. 5, there were concerns within Boeing BA -2.23%decrease; red down pointing triangle about the way the aerospace giant was building its planes. Boeing, like so many other American manufacturers, was outsourcing more and more of the components that went into its complex machines.

A Boeing aerospace engineer presented a controversial white paper in 2001 at an internal technical symposium. The engineer, John Hart-Smith, warned colleagues of the risks of the subcontracting strategy, especially if Boeing outsourced too much work and didn’t provide sufficient on-site quality and technical support to its suppliers.

“The performance of the prime manufacturer can never exceed the capabilities of the least proficient of the suppliers,” Hart-Smith wrote. “These costs do not vanish merely because the work itself is out-of-sight.”

[Joe in PNG]

The All-Holy Policy of Cutting Cost Above All appears to have hit the wall in this and many other industries.

One does wonder if those with the Right Degree from the Best Business Schools will see this fact, and adjust- or will they continue to venerate what's become Holy Writ?

[entropy]

Well fortunately/unfortunately, aviation has always had the backstop of physics and death to act as the great arbiter. Bernoulli will only let you bullshit so long.

[DC_P]

I think we’re both barking the same tune, just not realizing it.

I won't requote your entire post, but it is what I meant about you being more knowledgeable than me... Not sure about anyone else, but our Cat3 mins are the same for autoland and HUD. The HUD does give lower takeoff mins though.

I was surprised when I first started on the 75/76 and found out you could land without seeing anything. I can't remember most of what I did last week, much less what the symbology is from when I left it 17 years ago, but there was a captain call out at alert height verifying everything was good.

Edit to add - I flew the 300/ER and you are right, it is incredibly smooth and comfortable. The 757 was still better when hand flying imo. The 76 had a strangely over-boosted roll feel, whereas the 75 was a perfect balance. I didn't appreciate it enough until I left it (and when to the 88) but you never had to think about how much pressure/movement to use on the controls. It was intuitive and just felt 'right' in every aspect.

[GJM]

[ccmdfd]

For some reason every time I see that picture I think of



I watch way too many movies.

[DC_P]

For some reason every time I see that picture I think of



I watch way too many movies.

Air Israel - brilliant.