With Travel Halted, What Happens To The Planes? - Page 1
Forum section: electronics / general

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 09, 2020, 04:42:25 pm
content: https://youtu.be/D9uZmmoexUkI thought it was interesting.

author: Monkeh
author_rank: Super Contributor
timestamp: August 09, 2020, 05:03:19 pm
content: Also, this happens:https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/ec0e5875b315e9e5862585ae007cd448/$FILE/2020-16-51_Emergency.pdf

author: Gyro
author_rank: Super Contributor
timestamp: August 09, 2020, 05:40:32 pm
content: Quote from: Monkeh on August 09, 2020, 05:03:19 pmFrom the Background section:QuotePresumably it's another one that applies to all those 737Maxs that have been sitting on the ground around the world for over a year now - probably not the only valve!

author: Monkeh
author_rank: Super Contributor
timestamp: August 09, 2020, 05:45:40 pm
content: Quote from: Gyro on August 09, 2020, 05:40:32 pmPossibly, it depends on the valve design and orientation. They're not the same engines. If they ever get the Max back off the ground they'll be in for a complete overhaul first, I imagine.

author: Gyro
author_rank: Super Contributor
timestamp: August 09, 2020, 06:06:30 pm
content: I wonder how many 'Engine bleed air 5th stage check valves' Boeing have in stock!

author: IanB
author_rank: Super Contributor
timestamp: August 09, 2020, 06:17:13 pm
content: QuoteI get the feeling this means "a crash"

author: jogri
author_rank: Frequent Contributor
timestamp: August 09, 2020, 06:42:06 pm
content: Quote from: IanB on August 09, 2020, 06:17:13 pmNo, this means a descent with descent rates that may or may not be fully approved for passenger flights by the airplane manufacturer, followed by a landing at a non-ICAO registered aerodrome. This procedure may be followed by an unscheduled rapid disassembly either during the descent phase or during the landing.

author: Gyro
author_rank: Super Contributor
timestamp: August 09, 2020, 06:44:23 pm
content: Spade -> 'Earth inverting horticultural instrument'.

author: ConKbot
author_rank: Super Contributor
timestamp: August 10, 2020, 04:15:43 am
content: Quote from: IanB on August 09, 2020, 06:17:13 pmhttps://en.wikipedia.org/wiki/TACA_Flight_110They are keeping it optimistic.

author: paulca
author_rank: Super Contributor
timestamp: August 10, 2020, 09:24:45 am
content: Quote from: IanB on August 09, 2020, 06:17:13 pmPlausibly, but you'd be amazed at how far a full airliner can glide.... if it has altitude to do so.

author: WattsThat
author_rank: Frequent Contributor
timestamp: August 10, 2020, 03:31:03 pm
content: Quote from: paulca on August 10, 2020, 09:24:45 amNo doubt you are referring to this example:https://en.m.wikipedia.org/wiki/Gimli_GliderAny aircraft that crashes in an uncontrolled fashion due to the loss of power is the very definition of pilot error. There is no excuse for losing control of an aircraft due to a loss of propulsion. Period. You do not stop flying the aircraft until it is no longer moving.Aviate, navigate, communicate.

author: langwadt
author_rank: Super Contributor
timestamp: August 10, 2020, 03:42:49 pm
content: Quote from: Gyro on August 09, 2020, 05:40:32 pmIf you had read it you would know that it only applies to the 737NG not the Max, it has different engines

author: SeanB
author_rank: Super Contributor
timestamp: August 10, 2020, 07:06:57 pm
content: Quote from: Gyro on August 09, 2020, 06:06:30 pmLikely not many, the more important thing is how many can the manufacturer and the designated overhaul facilities overhaul per week, as those kinds of equipment are designed to be overhauled and repaired multiple times in their operational life. The more worrying thing is that many of the parts will have time expired during this period, and will need to be taken out and replaced, plus the majority of these aircraft are being stored in far from ideal conditions, and with far from ideal preparation other than put covers on and tape up ports. you will find many will have unseen corrosion, and many will have failures almost immediately after being placed back into service.Batteries as well are a worry, as they will have needed to be removed and stored in a battery maintainer that keeps them properly charged, but likely they are just left disconnected in the avionics bay at best, or have been left connected and thus have overdischarged to the point they are useless, or for the lithium ones, have dropped down to the point the controllers have deemed them unusable and failed them.Going to be a lot of the older fleet going into scrap metal as well, at least those that are fully paid off, so that the scrap price, after salvaging all saleable parts for other aircraft, is more than the cost of scrapping them. You are also going to find a lot of lease aircraft in a quandry, not worth much any more, still under loans, and not able to earn income, plus every month the bill for storage increases. Going to be a lot of airlines closing and merging, and quite a few national carriers (the one here for instance) are going to either need massive government funding, or will be closed, restructured or sold off.Friday was the first time I had seen any RJ's fly out of the airfields near me for some time, and there is a distinct lack of air traffic to the major airline as well, though there is still a fair amount of helicopter traffic, as most of it is for medical cases, and for military use.

author: Rick Law
author_rank: Super Contributor
timestamp: August 10, 2020, 07:31:02 pm
content: Quote from: jogri on August 09, 2020, 06:42:06 pm[RL: Bold added to quote]Pardon my ignorance, what does "unscheduled rapid disassembly" means? Is that some kind of airline lingo for the plane falling apart while descending for the landing? If so, this euphemism totally obscure the reality here.

author: peter-h
author_rank: Super Contributor
timestamp: August 10, 2020, 07:38:32 pm
content: Ignore it; he's playing with you.That valve jamming is potentially a loss of much or most of the engine power, which is bad news if it happens in both engines at the same time. Google BA038 for example.

author: langwadt
author_rank: Super Contributor
timestamp: August 10, 2020, 07:38:43 pm
content: Quote from: jogri on August 09, 2020, 06:42:06 pmand airliner doesn't just fall out of the sky because it loses engine power

author: langwadt
author_rank: Super Contributor
timestamp: August 10, 2020, 07:42:25 pm
content: Quote from: peter-h on August 10, 2020, 07:38:32 pmif the valve gets stuck the compressor stalls and the engine automatically shuts down and cannot be restarted

author: jogri
author_rank: Frequent Contributor
timestamp: August 10, 2020, 08:20:32 pm
content: Quote from: Rick Law on August 10, 2020, 07:31:02 pmIt's a term that is commonly used as an euphemism when a rocket decides to blow up. Afaik no airline uses this term (but SpaceX uses it to describe their landing failures), it's just a joke phrase like "the front fell off".

author: IanB
author_rank: Super Contributor
timestamp: August 10, 2020, 08:25:27 pm
content: Quote from: peter-h on August 10, 2020, 07:38:32 pmQuote from: jogri on August 10, 2020, 08:20:32 pm

author: sleemanj
author_rank: Super Contributor
timestamp: August 10, 2020, 09:26:41 pm
content: Quote from: WattsThat on August 10, 2020, 03:31:03 pmGimli might be the more famous, but Air Transat is way more pucker inducing...https://en.m.wikipedia.org/wiki/Air_Transat_Flight_236120km glide over the open ocean to the Azores (and they still had to lose excess altitude!). A good example of how airliners are more like massive self launching sailplanes than we give them credit for.

author: WattsThat
author_rank: Frequent Contributor
timestamp: August 10, 2020, 10:29:01 pm
content: That you for the Air Transat link, I was unaware of that event.I am not surprised that both pilots mentioned had glider ratings. With that experience, one learns from your first flight that without power, you get one and only one chance for a successful landing.

author: Rick Law
author_rank: Super Contributor
timestamp: August 11, 2020, 02:20:06 am
content: Quote from: jogri on August 10, 2020, 08:20:32 pmYeah, that's what I thought. A way over the top euphemism.

author: IanB
author_rank: Super Contributor
timestamp: August 11, 2020, 02:24:31 am
content: Reading the story of Air Transat was also disturbing. Two experienced pilots were flying a plane in which fuel was disappearing much faster than their flight plan said it should be consumed by the engines. So much so that alarms went off. And yet, when a tank was unexpectedly low on fuel, they pumped even more fuel into the empty tank and watched that disappear too. And then they said "Oops! We ran out of fuel!" If there was ever a case of human error, this was it.It's worrying, because although there is a place for checklists and standard operating procedures, you also have to think. You can't check your brain at the door and leave it behind.

author: SkyMaster
author_rank: Frequent Contributor
timestamp: August 11, 2020, 03:31:45 am
content: Quote from: WattsThat on August 10, 2020, 03:31:03 pmThere was also Air Transat Flight 236 that glided on a long distance before successfully landing (okay, it was a hard landing).But these all-engine-out landing are only successful in day VFR condition. At night or in IFR condition, gliding to a successful landing would required a tremendous amount of luck.

author: SkyMaster
author_rank: Frequent Contributor
timestamp: August 11, 2020, 03:56:49 am
content: Quote from: IanB on August 11, 2020, 02:24:31 amThe Air Transat Flight 236 crew were busy handling a low oil temperature indication when they observed that an automatic fuel transfer started sooner than expected. From that point the captain was trusting less and less the avionics of his plane. Also, the crew were in contact with the maintenance person from the airline and the crew followed the maintenance person instructions. Following the investigation, Airbus revised the A330 flight manual in regard to suspected fuel leak.Also, it is always easy to judge any crew decision, after all the facts are available and weeks or months are spent reviewing the event.The Accident Report, from the Government of Portugal, is available. It is only 103 pages long and easy to read.

author: Brumby
author_rank: Unknown
timestamp: August 11, 2020, 04:01:56 am
content: Quote from: WattsThat on August 10, 2020, 10:29:01 pmYou don't need to be any sort of pilot to understand that.

author: jogri
author_rank: Frequent Contributor
timestamp: August 11, 2020, 11:30:34 am
content: Quote from: sleemanj on August 10, 2020, 09:26:41 pmModern jets like the A320 or the 737 have glide ratios of 15-20 (sailplanes are in the range of 50-70:1), that means they can travel 15-20 miles for every mile they drop in altitude. If you start at normal flight levels of 10-12km you can glide up to 200km (or even more if you can use thermal updrafts). The main problem is that you have to get creative when it comes to slowing down as you probably can't use reverse thrust (and maybe even flaps if you are especially unlucky), if you don't have a rather long runway you might overshoot.Btw, if we exclude intentional stalls (that won't be gliding) you can't realistically achieve a worse glide ratio than 4-5:1. NASA used heavily modified Gulfstream jets as a training vehicle for Space Shuttle pilots, and they had to extend the gears and flaps and use full reverse thrust to get a plane that was as bad at gliding as the Shuttle (it just doesn't have big enough wings to be a decent glider).

author: langwadt
author_rank: Super Contributor
timestamp: August 11, 2020, 12:49:12 pm
content: Quote from: jogri on August 11, 2020, 11:30:34 amafaik thrust reversers are never a requirement for safe landing, it just saves on brakes and might help a bit if it is very wetthe A380 doesn't even thrust reversers on all it's enginesI think I've read some where that the glide ratio on a wingsuit is ~2 .5:1

author: ConKbot
author_rank: Super Contributor
timestamp: August 12, 2020, 01:21:25 am
content: Quote from: langwadt on August 11, 2020, 12:49:12 pmWouldn't be that surprising. Mike Patey filmed a stunt where a wingsuit flyer held the wingtip of his plane, requiring heaps of reverse thrust (negative angle on the variable pitch prop), so he could be in a step enough dive and not speed away from the skydiver.https://youtu.be/Jdccr7qm5NASo at least a couple hundred HP in reverse to begin to match their glide ratio.

author: jogri
author_rank: Frequent Contributor
timestamp: August 12, 2020, 07:01:24 am
content: Quote from: langwadt on August 11, 2020, 12:49:12 pmYes, technically thrust reverser are optional on a dry runway and you can land without them, but you shouldn't do it... This is what it looks like when you try to stop a 747 with worn out brakes without thrust reversers:The A380 doesn't have thrust reversers on its outer engines because those aren't over the asphalt of a normal airstrip and you would blow up a lot of debris from the ground/grass that then gets sucked into the engines.

author: langwadt
author_rank: Super Contributor
timestamp: August 12, 2020, 08:43:56 am
content: Quote from: jogri on August 12, 2020, 07:01:24 amthat's not a landing that is an aborted takeoff

author: jogri
author_rank: Frequent Contributor
timestamp: August 12, 2020, 04:45:10 pm
content: Quote from: langwadt on August 12, 2020, 08:43:56 amYeah, and a nominal V1 (maximum speed at which a start can be aborted) is around 160 knots while a landing with MTOW will get you in the same range (usual landing speeds are in the 130-150 knots range)... So the only main difference is that the tires never left the ground for the aborted takeoff, but other than that a fast landing produces a similar strain on the aircraft than an aborted takeoff.

author: langwadt
author_rank: Super Contributor
timestamp: August 12, 2020, 06:35:13 pm
content: Quote from: jogri on August 12, 2020, 04:45:10 pmat an aborted takeoff there probably much less runway left to stop on, braking is much much harderafaik thrust reversers are not even on the minium equipment list

author: jogri
author_rank: Frequent Contributor
timestamp: August 12, 2020, 06:54:59 pm
content: Well, every airplane with a certificate of airworthiness is capable of slowing down to a stop without thrust reversers... Albeit with significant damage to the landing gear, especially the tires.Btw, i just checked the MMEL for the A320, this is what it says about thrust reversers being inoperative:QuoteSounds like a "technically you can fly with only one reverser, but get it fixed ASAP". I'll take a bet and say that the airline uses this exception to get the plane to a workshop as soon as possible because every additional failure in the propulsion/breaking system is going to get the plane grounded.

author: langwadt
author_rank: Super Contributor
timestamp: August 12, 2020, 08:20:13 pm
content: Quote from: jogri on August 12, 2020, 06:54:59 pmsure brake pads and the time to change them cost money, buthttps://youtu.be/NkrozyWKCHY

author: cdev
author_rank: Super Contributor
timestamp: August 12, 2020, 08:30:19 pm
content: I suppose some could do what this man has done.. Live in one...

author: SkyMaster
author_rank: Frequent Contributor
timestamp: August 12, 2020, 09:00:59 pm
content: Quote from: jogri on August 12, 2020, 04:45:10 pmI would be surprised if it is possible to land a B747 at Maximum take-off weight (MTOW).The flight manual and SOP (airline standard operating procedure) probably limit the weight at which the B747 can land. And, after taking off at MTOW, the B747 would not be at MTOW anyway... because... fuel burn

author: jogri
author_rank: Frequent Contributor
timestamp: August 12, 2020, 09:05:55 pm
content: Quote from: langwadt on August 12, 2020, 08:20:13 pmThose are videos from runway 05R, the taxiway is at the end of a 3.2 km long runway so the pilot has to drive down the runway anyway to reach the gates... So why bother? It gives you a smoother landing, cuts down the time required to reach the gate and avoids the chance of foreign object damage. And since the plane doesn't land with its maximum take-off weight the brakes don't have to work that hard (a full 747 has fuel for 16h, and you typically have enough fuel for ~1h of flight left when you land, that alone can be a difference of up to 150 tons between take-off and landing)Quote from: SkyMaster on August 12, 2020, 09:00:59 pmWell, you could probably get it down in one piece but at the cost of a totaled airframe... Or you cold proceed to dump 100 tons of fuel, but that's going to take some time (probably around an hour given that you first have to find an appropriate spot).

author: langwadt
author_rank: Super Contributor
timestamp: August 12, 2020, 09:15:37 pm
content: Quote from: SkyMaster on August 12, 2020, 09:00:59 pmgoogle says: Maximum take-off weight for 747 is roughly 400tons depending on model, and maximum landing weight is roughly 100tons less

author: langwadt
author_rank: Super Contributor
timestamp: August 12, 2020, 09:21:40 pm
content: Quote from: jogri on August 12, 2020, 09:05:55 pmgoogle.. 747 fuel capacity ~200tons, fuel consumption London to New York ~70tons, time to dump 100tons ~55 minutes

author: langwadt
author_rank: Super Contributor
timestamp: August 12, 2020, 09:32:59 pm
content: Quote from: jogri on August 12, 2020, 09:05:55 pmlooks like landing a 747 at MTOW is not a big issue,https://www.boeing.com/commercial/aeromagazine/articles/qtr_3_07/article_03_3.html

author: SkyMaster
author_rank: Frequent Contributor
timestamp: August 12, 2020, 10:15:17 pm
content: Quote from: langwadt on August 12, 2020, 09:32:59 pmWait a minute, in a previous post you claimed the B747 Maximum landing weight was 100 tons less than the Maximum take-off weight, and now you are saying that landing a B747 at a weightnearMTOW isnot a big issue?The article you are referring to, at the beginning read "Landing overweight requires an overweight landing inspection with its associated cost.", and then near the end, read "...The Boeing airplane maintenance manual (AMM) provides a special inspection that is required any time an overweight landing occurs, regardless of how smooth the landing.".I think the article's intent is to claim that the Boeing 747 structure is designed to survive such anabnormal situation, without damage.

author: langwadt
author_rank: Super Contributor
timestamp: August 12, 2020, 10:36:42 pm
content: Quote from: SkyMaster on August 12, 2020, 10:15:17 pmyes, so while you should preferably to stay below maximum landing weight, if you have to, even a hard landing at MTOW isnot going to make the plane fall apart it just needs an inspection.one of allowable reasons for an overweight landing is "Serious illness of crew or passengers which would require immediate medical attention." If there was a serious risk from an overweight landing I doubt someone needing medical attention would be a good enough reason

author: SkyMaster
author_rank: Frequent Contributor
timestamp: August 13, 2020, 01:47:33 am
content: Quote from: langwadt on August 12, 2020, 10:36:42 pmWell, a hard landing on a large aircraft is serious situation. The option of landing overweight is going to be specified in the airline's SOP (Standard operating procedures).Below is what a hard landing can do:This occurred during a test flight; the test plan was not calling for a hard landing, the crew inadvertently did a hard landing. An FAA inspector was standing up at the time of the landing and the impact was such that he broke an ankle. And for the aircraft damage, you can watch the video, it is only a few seconds long. Among other things, you will see the fuselage flex like a wet noodle; but this is not all. And this was a DC-9; a little bird.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 13, 2020, 04:19:49 am
content: Best use of a thrust reverserSaab makes some intense-looking airplanes.

author: paulca
author_rank: Super Contributor
timestamp: August 13, 2020, 10:37:16 am
content: Quote from: langwadt on August 12, 2020, 06:35:13 pmOriginal video looks like flight trials. The rejected takeoff test has to be V1, maximum takeoff weight, no thrust reversers, the plane must stop on the runway and be able to exit the runway. Meaning it must be able to put the brake fire out and taxi under it's own power off the runway. Often when a rejected takeoff happens the brakes can go on fire and lock up, closing the runway until engineers can unlock the wheels.No thrust reverses is because rejected takeoffs very often happen when there is an engine failure and you can't really use thrust reverses without symetric thrust.Thrust reversers are usually banned at airports for out of schedule movements... ie. out of hours, like at night when there are stricter noise abatement requirements.On gliding an airliner (or anything for that matter) it's all about the number 1 gauge, speed. Fly the pitch/aoa to maintain the speed you need and take whatever descent rate you get. It's a recurring problem that airline pilots are so heavily trained in procedures, checklists and "flying the numbers" that they simply forget to "fly the damn plane".

author: langwadt
author_rank: Super Contributor
timestamp: August 13, 2020, 11:26:43 am
content: Quote from: paulca on August 13, 2020, 10:37:16 amasymmetric thrust must not be a big issue since the MMEL for the A320 allows for one nonfunctional thrust reverser

author: paulca
author_rank: Super Contributor
timestamp: August 13, 2020, 12:02:49 pm
content: Quote from: langwadt on August 13, 2020, 11:26:43 amThat's odd. "non functional" thrust reverser could also mean the actual mechanism has failed. The throttles come up to 80% or something on reverse, if one of the engines has a broken reverser it will be producing 80% forward thrust.I found this:https://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/safo/all_safos/media/2007/SAFO07007.pdfWhich states:QuoteWhich is line with my thoughts that if either engine or reverser is "out of operation" then thrust reversers (or at least thrust reverser beyond idle reverse) is not permitted.EDIT: Although reading it more clearly the accidents were because the pilot left the non-operating reverser engine in "CLIMB" position, rather than IDLE. It then states as to whether the pilots should move the throttles to IDLE REVERSE or MAX REVERSE is up to the airlines. I would expect the plane itself determines in either/both/neither reverser should be activated when one is failed.EDIT: Remember in a normal landing the braking is automatic. There is literally a "Auto brake selector" knob, usually, with positions "RTO, OFF, 1, 2, 3" or similar. It sets a constant retardation rate. 1 and 2 are common settings. The idea behind the the thrust reversers is not that the aircraft needs help to stop, but to reduce brake wear. The aircraft MUST be able to stop with 0 reverse in all conditions, including permitted snow/ice conditions for which the aircraft is rated.

author: langwadt
author_rank: Super Contributor
timestamp: August 13, 2020, 12:14:25 pm
content: Quote from: paulca on August 13, 2020, 12:02:49 pmthe way I read it the pilot should just make sure operate both throttles as normal and not only use the one with a functional reverser

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 13, 2020, 11:36:30 pm
content: Quote from: cdev on August 12, 2020, 08:30:19 pmLooks like a great home for the technical hobbyist. Turn the cockpit into a flight simulator complete with authentic instruments and controls (easiest way probably would be to build a shed around the front part of the plane, then add projectors for video), turn the cargo bay into a RF shielded lab. The wings would make great places to mount solar panels. Perhaps the fuel tanks can be turned into thermal storage tanks by adding insulation on the outside?

author: SkyMaster
author_rank: Frequent Contributor
timestamp: August 14, 2020, 01:20:23 am
content: Quote from: NiHaoMike on August 13, 2020, 11:36:30 pmI don't know if the B727 (this seems to be a B727) has any internal center tanks, but the wings are "wet wing"; where the outer skin of the wing is the fuel tank itself. Sealant is applied inside the wing structure to prevent the fuel from leaking. Maybe installing insulated tanks inside the wings would fulfill your need.

author: paulca
author_rank: Super Contributor
timestamp: August 14, 2020, 03:53:38 pm
content: No thanks, I'll live in one of these.