The goal was to make a spot landing exactly on a target then stop as aggressively as possible. However much distance that takes sets the baseline for what the airplane is physically capable of. All the landing performance data for day-to-day use are then derived by adding various safety margins to the original test data. e.g. (made up ballpark numbers) add in 1,000 feet for a more normal flare & touchdown maneuver, add 20% for worn-out brakes, add in 50% for less aggressive braking, etc.
These factory test pilots got a little too slow and their vertical descent rate really picked up in the last 20 feet. By which time there wasn’t much time to notice or correct the discrepancy. They didn’t exactly land; they more like impacted. But the front part did stop quickly. And safely.
Disclaimer: Professional pilots. Do not attempt at home. No wheels fell off in the making of this video.
That is an amazing video! Probably not in the report to the FAA: “For landing on particularly short runways, passengers in the last 3 rows should move forward to the cockpit. The rear exit will open immediately after landing, for ease of disembarkation.”.
As RP said, your uniform is whatever your company says it is. I’ve worked for companies that had them as part of the uniform, and one that didn’t (we wore personalized golf shirts, which I really liked).
The “bars” do help smooth things over when we travel in uniform. Frankly, it’s to a point that I consider it a fetish. I’m not supposed to talk about the particulars of airport security, but I fail to see why pilot uniforms are still part of it - after all, they are not controlled equipment. I believe this is a holdover from when procedures were changed after 9/11.
But here’s a way to remember how many stripes are on whose uniform:
4 bars means you can read and write
3 bars means you can read OR write
2 bars means you know someone who can read or write
Wow! Quite a video. Just after touchdown you can also see the forward fuselage noticeably flex - even had the tail not fallen off, there’d be some significant structural damage, I’d guess.
AF447 has always seemed a particularly haunting accident, I suppose partly because it took place in the middle of a stormy dark night in the middle of the South Atlantic Ocean, and partly because there was nothing really fundamentally wrong with the plane, other than transient icing of all three pitot tubes. But one thing led to another and the cockpit was soon in utter chaos. To a layman like myself, the scary question is, how do you protect against a modern jetliner suddenly and literally falling out of the sky over the middle of the ocean? It seems like the ultimate failure of the Swiss cheese safety model, where a whole bunch of random holes lined up in fatal perfection.
The following is a rather unusual narrative that was compiled from the four BEA reports, a book that was written about the crash, and a report from the French judiciary. The English is rather poor, with both the CVR transcript and the narrative somewhat badly translated in places. Some parts of the narrative annotating the transcript seem rather speculative, and there’s a bit of editorializing about things like alleged Airbus design faults. But overall it strikes me as an informative read for the average person, keeping in mind that it may not be wholly accurate or objective.
It is a haunting accident to read as a pilot because you can relate to the cockpit chaos.
I would disagree that there wasn’t something fundamentally wrong with the plane. It was flying at an altitude that required a narrow band of control input and that was fed by information from Pitot tubes. It was a cascade failure of systems that certainly overwhelmed the FO. Unfortunately it happened right when the Captain was away from the cockpit. there was a narrow window of opportunity to get the plane back on track and that window closed before it could be accomplished.
It utterly overwhelmed the computers that Airbus promised everyone would fly the plane so the pilots didn’t have to. Then the same computers took away the information the pilots might have used to recover the situation. Those dudes were not Chuck Yeager; more like Joe Average Sleepy Airline Pilot. But the airplane handed them a mostly insoluble problem & then kept dropping misleading jokers on the pile every time they did something that might have helped.
Say what you will about the 737 MAX debacle, but the FAA did not end up sweeping that one under the rug. Unike AF477 & the French BEA.
I know I’ve mentioned the before somewhere on the SD but if you want a great explanation of the AF 447 crash, get Understanding Air France 447 by Bill Palmer. No need to be a pilot to appreciate the material. Palmer is highly qualified but writes in a clear, easy to understand manner.
Investigators found the horizontal stabilizer actuator, which is part of the airplane’s pitch trim control system and is also referred to as the trim jack, had separated into two pieces. The actuator was found separated where the clamp nut threads into the barrel section. Examination of the threads inside the barrel and the threads on the clamp nut revealed that the two components separated by unthreading as opposed to being pulled apart in tension. A circular wire lock ring is used to prevent the barrel and clamp nut from unthreading. The lock ring was not yet located in the wreckage. This possible safety issue could result in a possible loss of airplane control.
I am not familiar with the DHC-3’s pitch control system. I assumed it used a cable-and-pully system like most light planes. Can anyone fill me in on how the DHC-3’s pitch control system works?
It sounds like a runaway trim situation. I can’t imagine it would even be possible to spin it out of the nut without hitting some stops. I’ve never been in a plane with power trim that didn’t have the shut off switch in a prominent location.
Magiver got it. They’re not discussing elevator control, but rather stabilizer trim control. A very common arrangement for that from big singles to widebody jets is a jackscrew oriented vertically spun by an electric (or hydraulic in big jets) motor. A large nut rides the jackscrew up and down as it turns. The nut is coupled to a lever connected to the leading edge of the stab itself.
if the screw turns too far the nut could be run off the top or bottom of the screw and then the stab flops freely up & down with airloads. So there’s normally a physical stop to prevent that. WHich physical stop seems to be missing from teh wreckage. Oops.
A different failure mode is the threads on the nut or screw failing, so the nut slides freely along the length of the screw instead of being locked in place by it. That’s what happened here:
In any case, the control power of an uncontrolled stab far exceeds that of the elevator. So you’ll get an unstoppable and probably very aggressive pitch up or pitch down. Might be violent enough to over-G the wings or the stab, causing them to fold. Or might not be strong enough to fail stuff, but be plenty strong enough to prevent control being recovered before the ground / ocean arrives.
I was pretty sure they were talking about the trim tab when I read the article. I might have flown an airplane with electric trim once, but I don’t remember. (It was a PA-28 Dakota.) The Schweizer had electric trim, which was very nice compared to the ‘on/off’ bungee system in the Robbo. I was confused about the accident aircraft because it never occurred to me that it would have a power trim system.
This isn’t a trim tab. Or at least probably isn’t. This is (probably) a trimming horizontal stabilizer.
The critical difference is a trim tab alters the aerodynamic balance angle of the elevator and has rather limited authority even at full travel. So it’s all but impossible for a malfunctioning trim tab alone to overpower the pilot’s ability to control pitch.
A trimming stabilizer OTOH has (usually) vastly more control power than the elevator. Making an airplane with a stab stuck in the wrong place potentially uncontrollable at any speed, much less at the current speed.
The value of having such a high-powered system is the ability to accommodate wide ranges of CG and weight. It’s also lower in drag at cruise speeds, but that’s more of a factor on large and/or fast airplanes than on something like a DHC-3.
Not quite. The corresponding move in the US would have been to have flown from someplace like Canada and landed in Washington DC on the National Mall.
Drug smugglers demonstrate nearly every day that it isn’t very hard to approach the US from the south from over land or over ocean and land on our territory within a few flight minutes of reaching the US border or shore.
The airport the defector chose is all but uninhabited except for the control tower. And is more or less in the middle of the Everglades, adjacent to one of the two highways that cross the 'glades linking the east & west coasts of Florida. It was built back in the 1960s during the heyday of light plane aviation and has been a bit of a boondoggle ever since.
Still and all, that was a fun story. I can’t imagine the Cuban authorities are too pleased with him or with his extended family right now.
I fly into Havana fairly regularly and it’s always interesting to see the array of Soviet-era antiques on display. None of which are formally display items, but instead are working, or at least potentially-working aircraft. Plus a few obviously derelict hulks slowly rotting through the pavement into the soil.
I fly around that area nearly every workday. We often hear USAF or FAA on the emergency hailing frequency trying to contact somebody someplace who’s headed to parts unknown. So obviously at least those folks have been detected.
Nobody, least of all USAF, has ever claimed US airspace is hermetically sealed against intruding lightplanes. Heck, if one was worried about weaponized lightplanes, there are about 1000x as many in the USA as there are in Mexico & Cuba combined. The threat, such as it isn’t, comes from within, not from without.
Risks Digest appears to be a rather paranoid place collecting all sorts of articles about bogeymen to be afraid of.
