Non-Military Aviation

[Shyster]

A very important new aircraft received its FAA certification today. The Cessna 408 SkyCourier is a twin-engine, non-pressurized, fixed-gear turboprop. Nothing about it is particularly new or innovative. It uses off-the-shelf Garmin avionics and tried-and-true Pratt & Whitney Canada PT6 engines, which have been around for more than 50 years. It's basically a flying cargo van. So why so important? Because this aircraft was pretty much developed specifically for FedEx, UPS, and other package shippers. It's been designed to carry three LD3 cargo containers, which means that shippers can preload packages into those containers and then load them into the SkyCourier in just a matter of a couple minutes. Every evening, hundreds of small "feeder" aircraft carry overnighted packages from dozens of small regional airports to larger hub airports, where they get loaded onto the mainline FedEx/UPS aircraft for transport farther on to the major processing centers. The process repeats in reverse early every morning. FedEx has ordered 100 of the SkyCouriers, and this aircraft will probably become a mainstay of overnight air cargo for decades to come. If you overnight a package in the future, there's a good chance that it will spend time on a SkyCourier.

[tifosi77]

I just overnighted a package the other day. Rats.

[NTP66]

A Chinese 737-800 crashed yesterday, and the video is horrifying. Basically went down completely vertical.

[shafnutz05]

A Chinese 737-800 crashed yesterday, and the video is horrifying. Basically went down completely vertical.

Flight tracker FlightRadar24 showed that the plane had sharply dropped from an altitude of 29,100 feet to 9,075 feet in 2.15 minutes. In another 20 seconds, its altitude was 3,225 feet, before flight information stopped.

I cannot imagine being in that plane. That's an awful long time to know you are about to die.

[dodint]

Another pilot suicide?

[NTP66]

Hope it's something like that as opposed to mechanical failure...

[NAN]

Just saw videos of the aftermath of that flight. Just horrible.

[tifosi77]

Boeing better hope that's the cause.

[NTP66]

Seeing as how we're flying cross country on a 737-900 in a few months, so do I.

[Shyster]

The 737 Next Gen is a mature product with more than 7,100 aircraft delivered over 25 years, and the 737-800 was by far the most popular model and accounted for around 70% of those sales. American and Southwest each operate more than 200 of them, United has more than 100, and Delta has around 70. If there was a systemic problem with the NG, I think we'd have seen it by now. I wouldn't be worried about that.

The high angle of the crash (nearly straight down) likely indicates either a significant control problem or intentional control input. As Juan "blancolirio" Brown said on his first YouTube video on this incident, aircraft want to pull out of dives. As an aircraft dives, its speed increases, and that increased speed produces more lift from the wings, which naturally wants to pull the aircraft out of the dive (given enough altitude, of course). Here, we have an aircraft that dove from 29,000 feet. Plenty of time to pull out of a dive from that altitude.

It could be lots of things, and might be something unexpected, but the first two things I can think of would be something that damaged/froze the elevator/stabilizer/trim systems, such as a jackscrew failure (like Alaska Airlines Flight 261), or an intentional act/pilot suicide (like SilkAir Flight 185 and EgyptAir Flight 990). The aircraft appears to have been at normal cruise one second and plunging nearly straight down the next. A stall wouldn't do that. Neither would an engine failure (or even dual engine failure).

[Shyster]

[tifosi77]

How long had Boeing 737s been in service before the rudder system failure at the heart of several rollover accidents was identified in the 1990s .

[scb147]

I believe the main 2 accidents for the rudder failures were United flight 585 (737-200) and USAir flight 427 (737-300). The 737-200 was introduced in 1967, and the 737-300 in 1984. Around of 1000 of each type were delivered by Boeing, not sure how many were in use before those crashes, but had to be many, many flight hours between them all

[Shyster]

Yeah, it was many, many years. And it took something like 5 years to identify the problem. The breakthrough came after Eastwind Airlines Flight 517 in 1996, where the aircraft experienced the rudder-reversal problem but the pilots managed to land safely. They were able to interview the pilots and test and compare the actual servo that had malfunctioned in flight. All of those servos were replaced with updated models 20 years ago. There's been no hint of any rudder problems since.

IIRC, there's an episode of Air Crash Investigation that focuses specifically on the 737 rudder reversals.

[scb147]

Yes, there is, I just watched that episode a couple weeks ago

[Shyster]

I'd also note there are substantial differences between the past rudder-reversal incidents and what happened to China Eastern 5735. The NTSB determined that the reversal was caused by thermal shock that occurred when the aircraft descended from cruise altitude, where it's very cold, to come in for landing in much warmer air. That's why the incidents were are fairly low altitudes. That low altitude also left the pilots with not much altitude in which to recover from the control malfunction. But China Eastern 5735 was at cruise altitude and had been there for a while, so it wouldn't have been subject to thermal changes at the time. And the pilots of China Eastern 5735 had well over 20,000 feet of altitude to correct the problem, but weren't able to do so. It could have been some other sort of control malfunction, but it doesn't fit into the past 737 rudder problems, which haven't appeared in the 20 years since Boeing installed revised servos.

[scb147]

I've seen some articles that mention that at least one pilot was not unconscious on China Eastern 5735 because around 9000 feet, the plane briefly ascended. I may be wrong, but even if there was a tail rudder issue, doesn't the nose want to raise when it's diving? If that's the case, I'm not sure a pilot would have to be conscious

[Shyster]

Blancolirio on YouTube said that the aircraft would want to pull out of the dive, and I certainly trust him (he's currently a 777 FO).

[tifosi77]

I'm not suggesting there's a similarity, just noting faults can be discovered well into a type's lifecycle.

Without some clear indicator I'm not inclined to believe this was pilot suicide. I seem to recall reading (maybe even here, of all places) that a large majority of survivors of suicide attempts report an immediate sense of regret upon initiating the attempt; it's almost like the impulsiveness of the moment is sort of contributory in a lot of cases. And however long this aircraft was in a steep dive is a really long time to think about it with all the physical forces at play constantly reminding you of what you're doing. Especially as there was an indicated brief recovery and climb before the final plunge. A more shallow dive that's less violent seems more likely if this was suicide (and I have seen reports that the impact angle was anything between 35° nose down and nearly vertical), but it's still very early days of course. Everything is still on the table.

[Shyster]

True. There are always errors or malfunctions that can take highly unique sets of conditions to happen. This very well could be something in that vein.

I'm very interested by the reports that debris was found far away. If that's a piece of a control surface, it could explain what happened. Although if it's something that is light and "fluttery," its possible that it might have just floated down that far. At the speeds that 737 reached in the dive—close to the speed of sound—it wouldn't have been surprising for parts to have been ripped off by the dive, not before the dive.

[dodint]

I used to know this but it's been a few years since I looked and I've completely forgotten.

If I wanted to buy a plane that can fly 350nm without refueling what would you recommend? Assume a private pilot certificate with IFR rating, but not necessarily a multi-engine rating (unless it makes sense). Prop only. No desire to exceed a service ceiling that would require life support.

[tifosi77]

Can't a basic 172 handle that range with 2 peeps on board?

[dodint]

Yeah. I realize now that I was thinking 600nm as the last time I researched this I was thinking of a different route. Which a 172 can technically handle but with not a lot of extra range, so I ended up looking at some larger Piper Archer's and stuff.

Looking back I think I was looking at Piper PA-28s and PA-32s.

Thanks.

[DigitalGypsy66]

Latrobe --> Morehead City?

[dodint]

Latrobe (LBE) to New Bern (EWN), actually. Michael J. Smith Field in Beaufort wasn't in the database I was using to check the distances.

I don't think Morehead City has an airfield.

The old distances were from LaCrosse (LSE) to LBE. I was surprised how much shorter it was to EWN.