An A320 flies 921 km with damaged left elevator. I don’t put much faith that the news got it right but they traveled from FIH to MJM.
They knew something was wrong with it. They took it to 30,000 feet and asked for right turns only.
commercial pilots, does this mean there’s some kind of adverse yaw associated with loss of the left elevator or is it due to an attempt to limit the use of one of the hydraulic systems?
I’m not an Airbus guy, so I’ll defer to @Richard_Pearse for anything beyond generalities.
In my Jurassic 737, if an elevator fell off cleanly (as in “was left off by maintenance and the absence unnoticed during preflight”) I’d expect to feel vibration. I’d expect any pitch input would generate a bit of rolling moment. I’d expect a small amount of undesirable and unexplainable yaw (not “adverse yaw” which by definition is yaw caused by aileron displacement). I’d have zero useful cockpit annunciations or indications; it’d all be feel & guesswork.
Now I think an entire elevator departing the aircraft in flight will not do so cleanly. Something is going to tear. e.g. If mechanics left out some bolts on some of the several hinges, the others might fail in overload & then the elevator is gone. Or if enough corroded structure gave way the elevator might tear out. But those failures won’t be clean. There would likely be jagged metal, more vibration, perhaps severe.
And there’d likely be a loss of hydraulics. On my jet (not an Airbus), I’d expect to fail both of our two hydraulic systems as the actuators get ripped out of the stabilizer. The good news is that a 737 flies OK without hydraulics. It’s wrassling a pig, but it’s doable. Of course that’s only proven to be doable with two intact elevators. With one missing & gosh knows how much damage to the stabilizer? Maybe it can’t be flown.
I find the idea of wanting right turns only to be mostly inexplicable. It might be something that makes sense within the context of Airbus in particular and the more elaborate warnings and backup modes the airplane may be equipped with.
The only other :eek: explanation I can surmise is that the airplane really wanted to roll one way or the other and they were afraid if they went too far it’d roll on its back and they’d be screwed. Although whether one ought to then request turns only towards or away from the rolling tendency is sort of an indicator of whether you’re a tic-tac-toe player or a checkers player. No chess players here.
As to the accuracy of the info in the article, when they say “elevator” they may well mean the elevator proper, or they may mean the entire horizontal tail. If the stab is much damaged, I have a hard time seeing the airplane remain flyable. OTOH, if what really happened was the stab, elevator, and actuators were fully intact but they lost a piece of counterbalance or balance tab or trim tab or actuator fairing or some such then we have a much more minor deal.
For damn sure I think it’d be very hard from the cockpit to have a good idea of what’s wrong. The conservative thing to do is land ASAP. The Alfred E Neuman thing to do is “What me worry? It’s not shaking too bad; let’s fly on to the destination.” While awaiting better info, I’d say the article’s bottom line is correct for the info we have: continuing to destination was a dumb decision.
Said another way: IMO if you’re worried enough to only want turns in one direction, you’re too worried to be doing anything except hustling down to the nearest suitable runway. Including preparing the cabin for a brace-for-crashlanding scenario.
OTOH … I don’t have any info on just how inhospitable the departure airport was. Africa has lots of area with darn few airports, and even fewer good ones. Flying some ways away might have been the least-bad option on offer. Taking it to high altitude and high Mach? Probably not smart IMO.
Here’s a picture for context:
I’m struggling to think of a good reason to request right turns only unless they were getting airframe vibrations when turning left which might have given them the willies and prompted them to avoid the situation. Another possibility is that pitching up would cause a right roll and in order to maintain height in a turn you need to pitch up a little. The resulting right roll tendency in the turn might have made them more comfortable turning right rather than left, but then you could suggest the opposite, that a tendency to return to level flight is more desirable. I don’t know, I’m clutching at straws a bit here.
As far as hydraulics go, the A320 has three systems, GREEN, BLUE, and YELLOW. Among other things, the GREEN system powers the left elevator, the BLUE system powers both the left and right elevators, and the YELLOW system powers the right elevator. Absolute worst case scenario would be the damaged left elevator causing a loss of fluid in both the GREEN and BLUE hydraulic systems. This would leave only the YELLOW hydraulics available and the following relevant systems would be lost:
If this happened, they would be rolling using a couple of spoilers only, no ailerons, and they will have lost some of their stopping ability when landing. The procedure also calls for a Flap 3 landing which would use a bit more runway than a landing with full flaps. This isn’t super significant as Flap 3 is a normal flap position for landing, it just has a slightly higher approach speed and needs a bit more runway.
If they did lose both GREEN and BLUE hydraulics and it happened during take-off, there a possibility they were left with the gear down and slats out. This seems unlikely but it’s possible.
I see that Mbuji Maya Airport is relatively short at about 6500’ and at an altitude of 2200’ above sea level. It also has “poor quality pavement” according to Wikipedia. Unless you had a dire emergency, it doesn’t sound like a great place to be landing with control problems so a diversion or just continuing to the destination is a reasonable thing to do depending on what the options are.
To summarise, there’s no simple technical explanation for why they would want right turns so presumably they were experiencing something funky that made that seem like a prudent thing to do. The worst case follow-on failures from a broken elevator are not the end of the world, but there are a few things to consider, and a nice long runway with adequate ground support would be a good place to be. The airport they landed at has a runway over 15000’ long.
Agree with @LSLGuy that flying high and fast is not a great idea with controllability issues.
Amazing what’s available on the internet these days. Plugging their departure and destination airports into Google gave me this:
What that shows me is that the other airports along the way are just as dodgy or worse than their departure airport. Ndjili might have been their only good option.
Edit: It is just a flight simmer’s tool, but the info is still useful.
I figured the destination airport was greatly preferred for whatever reason and climbing isn’t a bad idea either. I would think there’s a sweet zone to hang out in where the air is thinner and easier on the elevator. Knowing nothing about commercial flights I would think 20,000 feet would be a good altitude in case they lose oxygen. And I would expect them to slow it down to a comfortable operating speed to keep things from getting torn off the plane. 200 knots is still fast but it’s much slower than 500 knots and they need to burn off fuel anyway.
So are the elevators split? it looks like they lost half of the left elevator. If the 3rd hydraulic system can control it then they’re not in too bad of shape as long as they aren’t losing hydraulic fluid and I would expect some kind of notification in the cockpit.
Yikes, that’s quite a picture. I don’t know how many hinges the A320 elevator has, but 3 is typical on other jets. if that’s also true on the A320 it looks like the outboard one let go, and the elevator then tore in half just outboard of the center hinge, leaving the center & inboard hinges intact.
Given @Richard_Pearse’s info about the low quality of airports available, proceeding to the destination may well have been the least-bad choice, not mere “what me worry”. In Latin America we often depart airports where the pre-departure conversation goes like this:
If the cabin or cockpit catches fire during climbout, we’re making a hasty return to this (very difficult) airport ABC that we’re leaving. Anything less dire during climbout we’ll go to this other airport XCV that’s 50-150 miles away in the wrong direction. If we make it to cruise we’re pressing on towards the destination XYZ, net of any problems that might arise later that we can talk about then. Agreed?
The point being we often depart places you either can’t, or really don’t want to, try to bring a partly crippled airplane back into. The best emergency return field is often not a return at all.
To @Magiver’s points, all else equal climbing improves range and gives you a good TAS for a low indicated airspeed. As long as you keep the Mach low, what really matters for causing further perhaps fatal damage is IAS multiplied by duration. Or probably more like IAS^2 * duration. Keep the IAS low and the only way to minimize duration is to climb for better TAS. But you want to stay well away from high Mach numbers. Bad shit happens to airflow around damaged structure at surprisingly low Mach numbers. I agree the low-mid 20s is not a bad ballpark altitude to play that game in.
OTOH, once you have damage (or stuck flaps or gear) you have no idea how much your range has been compromised. All the preflight calcs that gave you enough fuel to reach the destination, plus a little slack, are now bogus. By the time you can gather enough data on distance covered and fuel consumed to know what your true range is, you may be a long way from where you started, but still a long way from where you’re going. Which is a bad time / place to learn that you can’t get there from here. Or worse yet, can’t get anywhere from here. Sucks to be you.
So flying lower than planned can get you in fuel trouble even if there is no damage. John Wayne-ing a lower altitude and also having damage of unknown fuel impacts is double trouble.
Any kind of hydraulic fluid or pressure loss will be accompanied by a cockpit warning. The left and right elevators aren’t mechanically linked so if one jams the other isn’t affected, however the range of movement is limited to prevent excessive twisting loads on the tail.
Are the left and right split (2 elevators each for a total of 4 control surfaces). If not, how is the 3rd hydraulic system for as it relates to the elevator system?
The elevators themselves are one piece per side with two actuators per side. In normal ops the left elevator is powered by the green system actuator (inboard) and the blue actuator (outboard) provides damping. If there is a failure the blue actuator can power the elevator. It is conceivable that significant damage to the left elevator could cause a loss of fluid in both the blue and green systems but it is also possible that the hydraulics would be unaffected.
What @Richard_Pearse describes is pretty standard airliner design of whatever manufacturer.
Each control surface is powered by 2 of the 2, 3, or even 4 hydraulic systems. In a kind of mix-n-match patchwork pattern around the airplane so that as long as any one system remains powered you’ll still have some ailerons / spoilers, some elevator / stab, and some rudder control.
Thanks Richard_Pearse and LSL for the info.
The delivery flight of the last 747:
Nice! It is a truly iconic aircraft. Everything else from the modern jet era is just “meh” by comparison.
There is nothing like it as freighters go.
That was a class act.
Definitely. But this? Not so much:
I wonder when someone will adapt an entire freakin’ 747 as a personal residence (if it hasn’t happened already; there are a hotel and an event center mentioned here, though):
People be wack. Both articles’ worth of people be wack.
I just watched a great analytical piece on Mentour Pilot about the Sriwijaya flight 182 disaster (9 January, 2021). It had a particular fascination for me because it shows how incredibly easy it is for these things to happen – how plain bad luck and a few lapses in training and company procedure can cause those holes in the Swiss cheese model of accident causation to line up.
For those who don’t like watching videos, here’s my layman’s brief interpretation. The autothrottle on this particular Boeing 737 had been malfunctioning on and off for years. Fixes would only last for a while and then the problem came back; specifically, when autothrottle reduced power, the right engine throttle would sometimes stick and refuse to throttle back.
That happened on this particular flight as they were making a long right-hand turn at low altitude in poor visibility just after takeoff. The right engine stayed at nearly full power while the left one was throttled back to about 46%, creating a large thrust asymmetry that no one noticed. Eventually the asymmetrical thrust sent the plane banking to the left instead of right, and when they got an audible “bank angle” warning, the captain noticed that the yoke was deflected fully to the right as the autopilot tried but failed to compensate for the asymmetry.
He naturally assumed without further confirmation that they were banking excessively to the right, and turned the yoke hard to the left. Since they were already in a dangerously extreme left bank, that created an upset that set the plane on its side, and sent it straight into the ocean.
I seem to recall hearing about someone who build a house utilizing parts of a dismantled 747, but that’s not the same as living in an actual intact 747. Like the article says, a whole 747 is just too big to transport by truck. IIRC the 747 hotel you mentioned has the advantage of being on or near an airport.
It seems like living in a 727 or similar sized plane would feel a lot like living in a mobile home, just due to the long, narrow dimensions. Although the 1500 square feet area quoted in the article does seem bigger than a typical mobile home.
ETA: I was thinking of the 747 wing house, which just repurposed the wings for the roof. The airfoil shape gives it a very mid century model look, which kind of makes sense; a lot of mid century design was inspired by aircraft.
No way to go up, snag, deflate and recover it, I suppose?