Max gross weight in the 747
Posted by Cal-Goat@reddit | aviation | View on Reddit | 195 comments

The maximum takeoff weight for most of our 747 fleet was 875,000lbs and it wasn’t often that we got right up to the limit, but sometimes we did, and frequently it was in Hong Kong or one of the major industrial cities of mainland China. This photo was taken in Hong Kong which naturally prompted the reaction “that’s a lot of rubber dogshit.”
The 747-400 was made to fly at these weights and didn’t really protest or wheeze its way into the sky as the classics were reputed to do at max gross. But taxiing was another matter. It was among my nightmares as a new captain (minimum radius turns and lithium battery fires being the others), and it was a delicate balancing act to begin rolling and forecast your momentum on the ground.
It starts with breakaway thrust which must be limited to some number I can’t remember now. I want to say it was in the neighborhood of 20% total thrust. Probably less. But on empty ferry flights, idle thrust was enough to have the big ship pulling like a puppy on a leash. So the heavy weight taxis were dramatically different in terms of technique.
The main risk was doing damage to people and objects behind you, including other airplanes. Sometimes you had to sit there at the taxi thrust limit for maybe 5-10 seconds before she would finally start to creep forward. Then it was important to manage that energy as you executed two 90° turns to get out of the Hong Kong cargo ramp. Those turns were where you would lose momentum. And the worst scenario was getting stuck mid-turn because it would take more than max-taxi thrust to get rolling again.
Two items of note on the screen: first, is that below “THRUST” are dashed lines. Normally we would derate the thrust from maximum available because we didn’t need it and it saved wear and tear on the engines. But in Hong Kong, with the heat and humidity and associated performance degradation, you needed everything she had.
The second thing to note is that we are taking off from 25L which points toward the city and the terrain. Hong Kong had such a complex engine failure profile for that runway that they taught it in the sim every year and it was a guaranteed event on your maneuvers validation. So the point is: of course you’re pointed at the terrain the day you’re at max gross.
Mercifully, my engines never gave me any grief. But I do recall one takeoff from 25L, probably very heavy but maybe not max, where I saw something that made me blink. The FO was flying and as captain, I had the responsibility to reject the takeoff if something happened. Somewhere between 100 knots and v1, I noticed a “REV” indicator above one of my engines, which normally indicates a reverser is unlocked.
Seeing that, my brain froze momentarily and tried quickly to analyze what was happening. We were still accelerating, there was no adverse yaw, no unusual noises. It must be a faulty indication. I said nothing and we continued. The REV indication remained until almost 10000’ but eventually went away. Your mind can rationalize the likelihood of an erroneous indication, but your gut won’t relax until you’re clear of the terrain.
That said, max gross takeoffs will boggle the mind of inexperienced pilots. You really don’t rotate until you’re well into the second half of the runway. It’s a vastly different sight picture and very disconcerting the first couple of times you see it.
For me, the most satisfying feeling was the high speed acceleration. Once she was clean and ripping along at her VNAV climb speed, she was truly in her element. A delightful and validating aeronautical experience, and one that I am so grateful to have in my logbook.
HashSlinger2001@reddit
As a pilot and engineer, what is the factor of safety on MTOW for aircraft? The pilot side of me says, and obeys to, “ZERO, NONE, NOT ONE LB OVER” but the engineer suggests “Wellllllll, there’s gotta be some wiggle room. Engineers always put in an FoS with their numbers!” I have never, and will never, exceed weight, but I want to know if someone has the answer. (I don’t work in certification so I have no idea. I am a pilot first and engineer second.)
Flying-Wild@reddit
Really interesting read.
If someone had an opportunity to fly the 747 now, would you recommend it?
Nyaos@reddit
Not the op but I fly one and love my job.
Over_engineered81@reddit
Do you fly the -400 or the newer -8?
Nyaos@reddit
We fly both at my airline!
Over_engineered81@reddit
Neat! Do you personally tend to fly one more than the other? Which do you prefer and why?
Nyaos@reddit
These days I tend to fly both about equally, though we have more -400s so normally I’d fly that more. Might just be due to my base doing more ultra long hauls.
I think I might prefer the -400. The -400 is less work to fly, and has a much better galley layout. It’s easier to land, especially in heavy crosswinds. The -8 ‘s huge engines hang low to the ground and are much easier to podstrike. (as you may have seen with UPS in Taipei lately). It might be older and have less quality of life improvements in the technology but those things are minor.
I do like the -8 a lot it’s just the nature of the plane makes for more challenging days. We often operate right on the max weight margins and because the engines are so efficient we always end up with too much fuel at the destination and are worried about landing overweight.
Prototype_Lemon@reddit
Yeah that -8 galley setup is horrendous. Whoever thought it was a good design to stack those containers one behind another should be hung.
Nyaos@reddit
The story that I've heard a few times is that it basically was Cargolux's fault. They were the launch customer of the -8F, and requested the galley to be that way for whatever reason. Boeing no longer wanted to alter configurations for specific customers as they used to do, so we are all stuck with it.
joesnopes@reddit
I used to describe the -400 as "the old man's aeroplane". Just about perfect in every way. One of those ways was the almost "self-landing". I'm told the flap changes on the -8 means it's a bit of a prick to land.
lucioghosty@reddit
I’m not a pilot by any means, but is the max weight due to carrying needed fuel + reserves? I assume that’s why you can’t take less fuel
indianmcflyer@reddit
Yes
Rook8811@reddit
I don’t travel very often but I seen a 380 no such luck on a 74 unfortunate
Cal-Goat@reddit (OP)
It was the best airplane ever. But I walked away because I wanted a better QoL. For many pilots now, it’s a stepping stone instead of the finale to a career as it once was.
Picklemerick23@reddit
Can confirm. Flew the 747-4/-8 for 2 years in between my US regional job and US legacy job. It was an incredible get but a stepping stone, for sure.
hoppla1232@reddit
A stepping stone to what?
Cal-Goat@reddit (OP)
Legacy airlines that don’t fly the 747 anymore (except Lufthansa). They pay the best and tend to have better schedules than most 747 operators now. UPS is the last 747 operator that pays pilots top dollar.
hartzonfire@reddit
Did Korean ditch theirs as well?
honesthibiscus@reddit
I’ve seen a Korean 747 landing at HNL a handful of times in the past year!
Cal-Goat@reddit (OP)
They might have a few left but I think they’re on their way out
DanTMWTMP@reddit
I’m loving every single word you write in this thread. You’re a great writer and you gave us all an incredible insight to a life of a pilot of The Queen; an insight that not many get to experience so this has been extremely informative, interesting, engaging, and fun to read.
Thank you so much for taking the time to post and comment!
Tricksilver89@reddit
Exactly this. I have an acquaintance who went from the regionals to flying 747s for Atlas for his second professional job in the airlines.
hoppla1232@reddit
Interesting, thanks for the insight
JPAV8R@reddit
I do and its a great job
AKcargopilot@reddit
Hah! Always HKG. When I used to fly for Atlas we often were right at max gross for takeoff and landing. Making the altitude restrictions on the way out were often impossible.
Alarmed_Investment_9@reddit
Pipboy
husky_whisperer@reddit
I’m no pilot and I’m sure this screen makes sense to pilots but…
That is the most batshit godawful UI I have ever seen
Cal-Goat@reddit (OP)
Haha, it’s extremely practical.
schruteski30@reddit
Ringing in at about 50,000 lbs per wheel. That’s a fully loaded large garbage truck on each wheel during taxi.
fresh_like_Oprah@reddit
all being motivated out to the taxiway by a blown, 2 stroke, V-12 Detroit Diesel
Haydn__@reddit
Wow Americans will use anything but the metric system (just kidding)
schruteski30@reddit
😂
That’s 7,692 AR-15’s per wheel!
Fun_Physics7689@reddit
What an awesome story. Been to Hong Kong in the 80s, and remember Kai Tak well. Thanks for this post. Hong Kong before 1997 and the Boeing 747 are two of my favorite things.
joesnopes@reddit
Amen to your comments about heavyweight takeoffs. The Classic and the 707 got very heavy in pitch at rotate at the higher weights with very forward CG positions as the Centre tank got filled. The -400's stab tanks fixed that.
It didn't change the distance down the runway at rotate. The 1500 feet markers were disappearing under the nose at the rotate call after nearly 4 kms since brake release.
Cal-Goat@reddit (OP)
Trivia: freighters did not have stab tanks.
Existing_Royal_3500@reddit
My closest experience was flying out of Guantanamo Bay on a loaded C-5 Galaxy. I was a passenger sitting upstairs in the tail of the aircraft. Upon lifting off from the runway the aircraft have to do a hard right turn to avoid flying into Cuban airspace. I am not sure what the difference is between max take-off on a civilian aircraft and military power setting on a military aircraft but that C-5 felt like it was gonna come apart. I remember putting my boots on the footrest on the seat in front of me to brace myself and the seats in front of me slid forward and as I looked up thinking "oh crap" I saw a sheet metal screw from the overhead panel work loose and fall out next to me and that was when the pilot released the brakes. That is when I realized what it felt like to be a gumball in a gumball machine. What an experience.
Cal-Goat@reddit (OP)
Was that the passenger compartment upstairs in the back?
Existing_Royal_3500@reddit
Yes, it was a small seating area separate from the crew and the seating faced backwards. You accessed it by drop-down stairs (picture pull down attic stairs).
Cal-Goat@reddit (OP)
I’ve been up there at an air show. Never had a ride though
Starlifter_141@reddit
This may be a stupid question but is there a sensor that tells you gross weight or is it all figured out by hand or the computer?
Cal-Goat@reddit (OP)
FMC knows basic empty weight, fuel sensors tell it how much gas, we tell it how much payload.
CommuterType@reddit
That’s the cleanest FMS I’ve ever seen
Cal-Goat@reddit (OP)
First thing I do when I get in an airplane is clean the screens. I HATE screen touchers
Fastmover1000@reddit
Great post! My max TOW in the A321neo is around 208K LBS and I know you carry almost 2X this weight in FUEL sometimes!
Scottzilla90@reddit
I’ve seen 1,050,00bs in a dash 8 747
joesnopes@reddit
Ours was 168 tonnes - fuel.
disillusioned@reddit
That... is an absolutely insane fact
indimedia@reddit
Thats a lot of oil! 🛢️ 🛢️🤯🛢️ 🛢️
Cal-Goat@reddit (OP)
Yeah but the tray table. And one thing that I did not like about the 747, probably the only thing, was that the cockpit windows didn’t open and so our windshield was always dirty. Some stations had special scaffolding that could reach the windshield to clean it, but I never got to see that.
zman12804@reddit
Very well written!
buttercup612@reddit
Thanks for pointing that out. I went back and read it. I didn’t even know there was a text mark to go with the picture. It really is well written.
blinkersix2@reddit
I second this
5amura1jack@reddit
The -8 during internal testing took off at a million and one lbs. The test pilots reported the bird didn't struggle to do it either, sad that the sun has set on that program.
Fart2Mouth69@reddit
what an amazing post, thank you!
DoomWad@reddit
As a guy who flies the 737, that Vr speed is 🤯
Hank_moody71@reddit
VR 178 is damn close to max tire speed on most jets. Google says it’s 204kts on the 747
ARottenPear@reddit
That's also 178kts IAS and max tire speeds are groundspeed. A 747 loaded to the hilt on a hot day in Denver could easily get pretty close to a groundspeed that high.
Hank_moody71@reddit
1000% ask anyone landing in aspen in the summer I know of at least 1 G200 that blew all 4 mains on landing due to this issue
drrhythm2@reddit
182 as a max tire speed seems to be fairly standard at least in the corporate world for some reason. I’m pretty sure it’s been that exact number for every type I’m flown.
Daft00@reddit
FWIW the A320 family has a max tire speed of 195 kts
atomatoflame@reddit
CL65 was 182kts if I remember correctly and that is basically a bastardized corporate jet. 737 is 195 for NG and 204 for the Max. It's probably related to the tire size and weight of the aircraft. In Denver on a hot day we get very close to tire overspeeds during rotation, but also don't want to drag the tail. It's a balancing act for sure.
fly_awayyy@reddit
777-300ER has similar speeds for the high speed tires to use its maximum take off weight.
cancerous_176@reddit
Very well written boss. As a wrench monkey I have always found what the other side of the fence does interesting, especially once you get into the big leagues with heavies. This post was awesome story, the only thing that could have made it better was over breakfast at a Waffle House over a cup of coffee. 🤣
Lump-of-baryons@reddit
Im just a lurker here but that was a great read, thanks for posting all that.
DaimonHans@reddit
And how much are they charging for 20kg luggage?
Objective_Piece_8401@reddit
Probably a dumb question for my pilot friends. If max taxi thrust was 21%, could you idle 1 and pop 4 to 42% (less, i know but trying to draw an easy picture) make a turn when you lost momentum?
Cal-Goat@reddit (OP)
Differential thrust wasn’t really helpful in my experience. It was always better to have all four engines running at a similar thrust. I’m sure that the max taxi thrust limitation had some margin built into it, but I didn’t want to test the limits and cause property damage or hurt somebody
manavcafer@reddit
Question fuel weight measures ton gross weight in lbs why ?
Cal-Goat@reddit (OP)
As far as I know, airlines can set their weights to either imperial or metric. I’m in America so all the airlines that I have worked for have used pounds. Although I know Atlas uses metric
JPAV8R@reddit
Good write up.
Breakaway thrust is no more than 40% N1 but you don’t really need that much. Did you ever get to fly the -8? They are marvels.
deleted_by_reddit@reddit
[removed]
grackychan@reddit
Legendary rewrite mate, thanks for this
DanTMWTMP@reddit
I knew what I was getting into from the first sentence. I read the whole damn thing anyways as is tradition, and smirked and chuckled along the way. hahahahaha good one.
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TheRoblock@reddit
A mechanic told me as long you can stick two fingers in between, you're good. I once loaded a MTOW aircraft as a loadmaster. I shat my pants a little when I saw the aircraft rolling, because... i mean... 412 tons if I remember correctly was the MTOW. Yea she took off just fine :)
Cal-Goat@reddit (OP)
The LITERAL book requirement for strut showing on the preflight inspection was “some”. They loved asking that question in the training center
TheRoblock@reddit
Obviously precise science
828jpc1@reddit
That’s more than a C-5! Wow!
Notonfoodstamps@reddit
Officially
828jpc1@reddit
Yeah, I know a couple C-5 drivers…I’ve topped them off before.
sportmonday@reddit
Makes my 737 seem tiddly!
Designer_Buy_1650@reddit
At that weight, was the flaps up speed above 250 kts?
hoges@reddit
I fly A321N and our clean speed is >250kts at heavy weights so I would assume it's the same case for a heavy wide body
Designer_Buy_1650@reddit
Does the 321 have the same wing as the 320? Thanks.
hoges@reddit
Yes, with a few minor changes. The 321LR is already pushing the limits of the wing and the XLR is going to push that even further
Designer_Buy_1650@reddit
Wow. Thanks
Selway00@reddit
Great write up! Silly question but how does a plane know what its own weight is? Do they have some sort of measuring device on each landing gear?
British_Rover@reddit
I can answer a different way. I worked for UPS on the air side but not as a pilot. Cargo is loaded into air containers that are weighed and marked before being rolled into the airframe. I had several employees that were in charge of weighing and final inspection of containers after they were loaded and I sealed them.
My air hub has three different sizes of containers. I can't remember the names of the types anymore as it's been over a decade now. The short containers were for the belly, were only about 4 feet tall and were a bitch to load. The two other containers were large enough for any normal person to stand in. Once all the containers were loaded, weighed and verified that manifest went to the load planner. He would make sure the plane balanced properly and that final cargo weight would be added to the plane.
Selway00@reddit
That’s really interesting. Thank you!
Cal-Goat@reddit (OP)
We know the basic empty weight. Then we add fuel weight, cargo weight and people weight. The airplane doesn’t know how much it weighs. We tell it how much it weighs.
Selway00@reddit
Thanks! That makes sense. So you are reliant on somewhat accurate measurements of cargo and people?
When you’re close to max weight, is there ever a concern that someone got it wrong and your actual weight is significantly more than your max takeoff weight?
HarryTruman@reddit
Yes and no. Someone more qualified can chime in, but it’s going to wholly depend on the plane and atmospheric conditions. I mean you obviously want to be as accurate as possible, regardless. But the definition and importance of “somewhat accurate” will be vastly different when comparing a 747 to a Cessna 180.
ywgflyer@reddit
You have to tell it what your zero fuel weight is (how much you weigh with all the payload but before you load a drop of fuel). This number gets inserted into the performance page (PERF INIT). The plane then knows how much fuel it has by way of tank sensors, and simply adds the two numbers to get your total weight.
Drunkenaviator@reddit
The ERF could go up to 910,000lbs.
Loose-Cicada5473@reddit
Before V1, curious why it wasn’t an automatic rejected takeoff, but such a great story, thanks for sharing.
Cal-Goat@reddit (OP)
100 knots to v1 we only reject for a fire indication, a red warning, loss of directional control or some very terrible horror like maybe an airplane crossing the runway in front of you.
Some study determined that a lot of bad things happen when you reject in the high speed regime so they limited the scope of abort criteria above 100 knots
fresh_like_Oprah@reddit
I worked two high speed RTO whales in my 747 days. JFK -NRT so they were heavy. It was tires and brakes all day while the jacks sunk into the pavement. I also saw what happened when a TWA L-1011 actually took off and then put it back down. That planed burned up (but everybody got off)
psunavy03@reddit
My jet weighed much much less than that. But the principle was the same, above 100 knots you take everything flying except for a few things I can't remember all of anymore. Fire, fuel contamination, engine failures, a few others.
It's the whole "difficulty of making this thing that's trying to go as fast as it can suddenly do the opposite" thing, in the runway remaining and without losing directional control. Often not the easiest proposition.
Cal-Goat@reddit (OP)
Yes, the principle applies to any transport category airplane with more than one engine
ewerdna@reddit
Is there an emergency stow option for the TR?
Cal-Goat@reddit (OP)
No, as I recall the QRH said that if you had a reverse indication with no adverse yaw or noise, then you would continue as normal. If you did have adverse yaw indicating that the reverser had indeed come open, you were supposed to maintain directional control, and land as soon as possible.
greatlakesailors@reddit
Yup. Just because it's possible to stop from below V1 without a runway overrun doesn't mean you'll do so for every issue. High speed rejected takeoffs are absolute hell on all the moving parts of the landing gear. You will probably heat the brakes to glowing / smoking and then that heat will blow out a few tires after you stop. There's a risk of losing directional control. At the very least you're taking the plane (and possibly the runway) out of service for long enough to screw up everyone's schedules.
From 100 knots to V1 you only reject if the plane seems likely to crash, burn, or otherwise give you a real bad day if you were to let it fly. Beyond V1 you only reject if the plane is physically unable to fly.
Gunner5091@reddit
How do they weight the payload on an airplane? They don’t weigh every passenger nor the carryon.
Cal-Goat@reddit (OP)
For passengers they use a seasonal average. This was cargo. The pallets were weighed in the warehouse before being sent out to the airplane.
Gunner5091@reddit
So in reality it is an estimate not an actual measurement of weight. I thought maybe passengers plane have a sensor of some sort. Thank You for your reply.
No-Bar3380@reddit
Is it not true at all that planes can weigh their weight on wheels through measuring the degree of strut compression?
Krampus_Nemesis@reddit
Strut compression wouldn't be a very reliable way to measure weight since it can vary with temperature, strut fluid quantity, and initial nitrogen precharge in the strut.
No-Bar3380@reddit
Illuminating, thanks!
Cal-Goat@reddit (OP)
Correct. I think in the US right now passengers are calculated at 170lbs during summer and 190lbs during winter. Children are less and I want to say bags are averaged at 30lbs. Not 100% sure but something close to that.
eljunbo809@reddit
Wouldn’t it be the other way around 190lbs during summer and winter 170lbs. Because of density altitude during the summer ? Student Pilot here. Thank you.
LostPilot517@reddit
No mass is mass. Performance calculations are done to account for density altitude.
Typically the adjustment is 5 lbs between summer and winter to account for heavier clothing in the winter months. Where winter is heavier, than summer weights.
LostPilot517@reddit
In FAA land, Airlines are now required every few years to weigh an average sample of passengers to establish their average weight.
Seasonal adjustments are still made, I believe it is still a 5lb difference here in the US.
MrFickless@reddit
25L should be pointed toward Macao no? The 07s are the ones that face toward the city.
Cal-Goat@reddit (OP)
Yes i got them flip flopped. Added a comment about that.
avi8tor@reddit
damn my mom is heavier
Hodgetwins32@reddit
Mama so big the airport by her had to get an ODP
LateralThinkerer@reddit
We all know.
bdubwilliams22@reddit
How can you be an av geek, read this and not love this post. I wish we got more them. Thank you for sharing.
WhyIsLifeHardForMe@reddit
Exactly the stuff I want to see here, very interesting both aviation wise and engineering wise
UW_Ebay@reddit
Another legendary post. So good. Thank you 👏🏼
cat_prophecy@reddit
The "rubber dog shit" comment just killed me. It's such a throwaway line in that movie I am surprised you remember it!
WorstDotaPlayer@reddit
This came into my feed for whatever reason and I'm glad it did. Really fascinating read, OP.
realsimulator1@reddit
This was well worth the read! It reminded me of Balleka making MK 747 videos in Hong Kong and Macao while taking off or landing with the beast fully loaded!
Bigcock1234@reddit
Can you nerds tell me what this fallout 76 lookin shit says? Thank you
Heavy-Ad5385@reddit
That was incredible -thank you so much!
One question and sorry if it’s a stupid one (not a pilot, just a plane fan)
The gross weight here is 876,700 and you mentioned that the maximum gross take-off weight is 875,000. What is the maximum permitted over? Does it depend on the way the plane is loaded, the passenger/cargo split? Or weather/humidity/airport altitude?
I always assumed “maximum” was a definitive limit so I’m intrigued as to what would be acceptable margins?
Thank you, and keep the stories coming 🙌
Cal-Goat@reddit (OP)
Maximum ramp weight is slightly higher (I can’t remember, maybe 4k lbs?) and we usually calculated 2000lbs for taxi burn.
CUNT_PUNCHER_9000@reddit
Excellent read, thanks for sharing
silverfstop@reddit
Forgive my ignorance… Is that way to establish via pressure sensors in the landing bogies
Cal-Goat@reddit (OP)
No. Input from our weight and balance data via our loadmaster. The FMC only knows the basic empty weight, it adds sensed fuel weight, and we tell it how much payload was added.
Cal-Goat@reddit (OP)
EDIT: my jet lag addled brain got crisscrosed- the 7s take off toward the city and the 25s point at the ocean. Hopefully the point isn’t lost from that error
AirborneBapple@reddit
What is he saying about the runway? 25 runways at HKG all point towards the Macao side. Maybe he took off on 07R, it makes more sense considering he’s closer to the terrain and pointing towards the city like he said. I’d love to know more about the engine out procedures too.
Cal-Goat@reddit (OP)
If you take off from the 7s, there is no special engine failure procedure. You can just climb in a straight line and not have to worry about obstacles or terrain.
cyrilleni33@reddit
I was wondering the same as the other poster : respectfully sir, I think you are mistaken as the 07's are the ones facing the city and the terrain, and the 25s are facing the Pearl River delta and Macau in the distance.
It was a great read nonetheless.
Cal-Goat@reddit (OP)
Haha, you are correct! My jet lag addled brain has embarrassed me once again!
cyrilleni33@reddit
That adds even more credibility to the rest of the story haha. Thank you again for sharing. I love HK and I lived there a while ago and loved every bit of it.
Mao_Kwikowski@reddit
C-17 doesn’t even get close to the Queen. 585k MTOW.
rhumbable@reddit
I think you mixed up 25L for 07R there. The 25 runways go over water, 07 runways head towards the city and terrain. 07C EO procedure is the worst via TEGUB. 3 different engine failures in one chart. Absolutely ridiculous. Not sure what HKCAD was thinking when they made that. Would really like to know the thought process behind it cause usually there's a legitimate reason. But luckily it's barely ever used.
AV8ORA330@reddit
What was max ramp weight. If memory serves it was also 875.0. So overweight for taxi…
Cal-Goat@reddit (OP)
I can’t remember. I want to say 4 or 5 thousand pounds more.
strandy76@reddit
What's that in civilized money?
Cal-Goat@reddit (OP)
Almost 397kg.
Interestingly, that airline ran into at least 1 conversion error that caused an airplane to take off about 45000kg overweight and the pilots didn’t notice until halfway across the Atlantic when their fuel burn calculations were too high. Fortunately they diverted safely but we continued to use imperial measurements even though most of our customers were metric.
DoughboySwoleboy@reddit
A lot of this sounds very familiar to the airline I used to dispatch/flight follow at, did it happen to operate out of Belleville, MI?
Cal-Goat@reddit (OP)
I’ll only say that some of our classroom days were catered by Hungry Howie’s 🤣
MessyMix@reddit
Hong Kong as in the old Kai Tak airport or the current airport? Terrain sounds like the old one.
Cal-Goat@reddit (OP)
Nope. I’m too young for Kai Tak although I’ve made pilgrimages to the old runway and checkerboard. This was Chep Lap Kok
SirLoremIpsum@reddit
More stories! more more!!
chandris@reddit
This is very interesting, Thank you. I assume C.G. is centre of gravity but can someone explain how the 20.9% figure indicates this. Thanks.
Luna_Parvulus@reddit
The center of gravity is listed as a percentage of mean aerodynamic chord, which is basically the width (front to back) of the average straight wing that would have the same calculated properties of the actual wing. So the CG is found at that position of the MAC on the airplane (taking in account the distance from the from of the airplane to the leading edge of said wing)
h3ffr0n@reddit
It is indicated as at what percentage down the Mean Aerodynamic Chord line the C.G. is located.
Cal-Goat@reddit (OP)
I believe it’s indicating a percentage of the mean aerodynamic chord. But I have no idea what that number signifies in any practical sense to the pilots because I did not pay attention to it.
Beahner@reddit
This….this why a plane geek like me loves a sub like this. These moments of getting a great experience that is well written and fantastically colorful as to the job.
Amazing share!
Tokyoos@reddit
So much better than your typical "identify this easy to identify airplane...."
CarrowCanary@reddit
Points at r/WhatIsThisPlane
Jetblast787@reddit
Can I subscribe for more niche 747 facts? Pretty please?
Cal-Goat@reddit (OP)
I'm bound to post something similar again.
UnrealBeing446@reddit
Awesome post! What was your fuel load for a flight like this?
Cal-Goat@reddit (OP)
Depends. HK we were almost definitely flying to Anchorage at those weights so probably 250,000lbs give or take.
Twa747@reddit
That v1 Vr split is sexy
jonsey737@reddit
Long time to keep on going after loosing an engine lol
Cal-Goat@reddit (OP)
V1 cuts in the sim were always max gross weight and yeah, that was a long time to wait for rotation
drrhythm2@reddit
That seems like such a high rotation speed compared to the corporate jets I fly.
henkie316@reddit
Do you feel the weight of the plane after rotating as well, compared to a lighter plane?
Cal-Goat@reddit (OP)
Yeah. It’s not dramatically different but enough to be noticeable.
CannonAFB_unofficial@reddit
What that was the rest of the TOLD like? Vmca and Vmcg?
LostPilot517@reddit
Those numbers are always equal to, or less than Vr. So, we didn't need them displayed.
Cal-Goat@reddit (OP)
I’ve never seen those number with takeoff data in the civilian world.
nbd9000@reddit
no flaps 20?
Gamestar63@reddit
TOGA BABY!!
BigDiesel07@reddit
I love the way you write
Cal-Goat@reddit (OP)
Thank you.
quemaspuess@reddit
One of the best posts I’ve ever seen on Reddit. Thanks for sharing
revolutiontime161@reddit
Damn that’s heavy, is that operational or structural max tog ?
ywgflyer@reddit
Max ramp weight. You can be over structural MTOW to taxi but you have to burn down to max takeoff before you actually start to roll. Usually accounted for in the taxi fuel on the flight plan.
cincinn_audi@reddit
Thank you for taking the time to share these special memories with us. As a non-pilot, I am curious in what situations one might want the Ref speed to be different from V1, VR, V2, etc. I noticed that some of the corresponding Ref speeds are set higher, while others are below. What's the relationship between a given ref speed vs the speed for decision, rotate, and takeoff?
Cal-Goat@reddit (OP)
I think those ref speeds are just boilerplate factory speeds based on weight. The big numbers on the left are fine tuned to current conditions like headwind component and runway friction conditions. So on a dry, calm wind day they should be nearly identical
cincinn_audi@reddit
Appreciate your response and that makes sense!
Accidentallygolden@reddit
So you take of at 876T in a plane with max gross weight 875T?
Cal-Goat@reddit (OP)
You would expect to burn about 2000lbs for taxi. Sometimes more.
JunkbaII@reddit
Fuel will be burned off during taxi
stubb5y22@reddit
Taxi fuel
Dadto4Kiddos@reddit
Awesome post thank you… as I was starting out as an A&P my dream job was to get on with UPS and work on those 747’s. But 9/11 changed so many things in the aviation industry. Ended up in the business jet sector.
neurotichamster8@reddit
The big delta from v1 and vr is due to the weight I presume?
Cal-Goat@reddit (OP)
Correct. The heavier you are the more distance required to both accelerate and stop, so you tend to see that spread as heavy weights. As soon as you run out of available stopping distance, you have to take it in the air regardless of what went wrong
m149@reddit
Nice read, thanks for writing it up!
forgottensudo@reddit
Thank you
okletsgooonow@reddit
Pilots can write well too it seems. Thanks for posting.
350smooth@reddit
This was a good read as a 73 guy. Thanks for the post. How often are you guys maxed out vs. empty?
Cal-Goat@reddit (OP)
I feel like max was maybe 10% if that. Probably another 10% was empty. And then the remaining 80% was everything in between but it definitely trended towards heavier weights, because if you’re going to spend 747 money, it really helps if you can fill the thing up.
Cautious_Bass7192@reddit
fucking badass post, lovely technical details, thank you for the enthralling read ~ a lowly aerospace engineering
JackRiley152@reddit
Great write-up, thanks!
ScarHand69@reddit
Well written. Anecdotes like yours are what make this sub so great.
AdeptBackground6245@reddit
Yes but can it play Tetris?
RS5na@reddit
Excellent post, thanks.
Magooose@reddit
My weight is pretty gross too.
Dry-Marketing-6798@reddit
I miss tapping on an FMS or similar. Not that I flew 747's. Islander BN2T😉