Bleeding Out Over San Francisco | Pan Am 845

this is the story of pan am flight 845. on the 30th of july 1971 a pan am 747 was on the ground at san francisco international airport on that day it would be flying all the way to tokyo's haneda airport the crew boarded the plane at 2 30 pm and began to prepare the flight to japan by 301 pm flight 845 filled with 218 people they were ready to go as the 747 pushed back from the gate the pilots had a curveball thrown at them they were planning to take off from runway 2 8 left but that runway was closed for departures their next choice of runway with zero one right but the first one thousand feet of zero one right was off limits to the seven four seven the pilots had a decision to make to get more information on everything they decided to talk to dispatch they informed dispatch about all the closures they realized that runway zero one right was long enough to accommodate a 747 then a radio call came in talk to tower the thousand feet they were talking about that's closed is actually overrun you couldn't start from that point in any event because of thrust damage start at the painted threshold and you still have 9 500 feet plus clearway ahead of you under those circumstances the page using 3a power shows no takeoff limitations at your gross end quote long story short they could take off the flight crew and the flight dispatcher discussed everything a bit more and came to the conclusion that the pilot should use flaps 20 for this take-off instead of the 10 degrees that they had originally planned for in the cockpit the pilots read out the v-speeds for this takeoff v1 was the speed at which you could no longer safely reject a takeoff that was 149 knots and the rotate speed was 157 knots soon the huge 747 was on the displaced threshold of runway 0 1 right ready to go at 3 28 pm the crew got their takeoff clearance and all four engines were advanced to take off power as the plane picked up speed the first officer called v1 the plane accelerated to the rotate speed and the first officer noticed something strange the end of the runway was fast approaching and they were still on the ground they pulled back as hard as they could in an attempt to lift the giant 747 into the air they were out of runway the pilots felt a bump as the runway ran out but the plane lifted off at the very last second usually takeoffs like these leave a very long tear on the tail you might even lose pressurization but usually you're in a position where you can safely land the plane but the state of flight 845 was much more dire the flight engineer looked at his panel and he realized that they were losing hydraulic systems one three and four he launched himself into the emergency checklist for those systems a member of the cabin crew came into the cockpit and they had some bad news a few passengers were badly injured at the end of the runway there were these lights that were put on top of long thin rods the plane flew through them and those rods punctured through the skin and into the cabin into a cabin full of passenger status the injury sustained by the passengers were not minor bumps and scrapes either some people had life-threatening injuries the pilots needed to put this plane back on the ground as soon as possible but it's not as simple as coming back in for a landing for one thing the plane was fueled up for an intercontinental flight to tokyo and so they needed to dump some fuel to make sure that the plane's weight was within limits for a safe landing more importantly they had no idea of the damage sustained by the plane they needed to know what worked and what didn't before making a landing attempt you don't want to be in a situation where you find out that something important doesn't work when you're on short final with the passengers being tended to by the doctors on board the pilots pointed the 747 out into the white pacific ocean to dump some fuel and to do some control checks the next hour and 42 minutes were spent over the pacific ocean the pilots met up with a u.s coast guard aircraft that was able to observe the damage sustained by the 747 it wasn't pretty the right body gear was missing and the left one was just hanging there after those checks the pilots were ready to land this plane they made an approach to runway 2 8 left the captain noticed that he had less and less elevator authority as the plane slowed the 747 touched down and the pilots tried to slow the plane it wasn't slowing down as fast as usual in addition to that the pilots were having a hard time keeping the plane on the center line 5300 feet down the runway the plane veered to the right and left the runway entirely once the plane came to a stop the 747 tipped over and came to rest with its nose in the air it's absolutely incredible that everyone survived for example a few rods went right through the seats 45f and 46f had those seats been occupied it would have been really bad once on the ground the damage to the plane was clear as day the gears were damaged the flaps the vertical stabilizer the horizontal stabilizer the brakes the brake valves the engines wait you know what i'm just gonna stop a lot of things were broken on this plane if i were to list everything that was broken we'd be here a while so that brings us to the big question how does a 747 almost not take off did they have enough runway yes the first thousand feet of runway zero one right was out of commission but that still left 8 500 feet for them to use the thing is a 747 can't take off with 8 500 feet of runway the reason the first 1000 feet of runway was off limits was because of what's known as a displaced threshold the 747 could only take off 1000 feet down the runway as there was a highway nearby and they thought that the jet exhaust would cause accidents on the road they had enough runway why didn't they take off to understand why we need to take a look at what happened that day at first they were planning to use runway 2-8 left one of the longest runways at sfo but that runway was closed for departures and the pilot only got to know this after pushback flight controllers at pan am's dispatch office did not check to see if the runway was actually operational they thought that it was business as usual that's why they told the flight crew to use runway 2 8 left here's a quote the flight controller assumed that all conditions were routine and did not check available information sources he was subjected to one of the most insidious hazards facing any routine operation that of being lulled into a sense of complacency end quote this led right into mistake number two the planes being pushed back and the pilots realized that runway two-way left isn't operational so they called dispatch to see what runway that they could use the dispatch officer ruffled through his charts which listed the usable runway for each aircraft type and right there it said that the boeing 747 could use 9 500 feet of runway on runway 0 1 right well that was more than enough for a 747 case close right well here's the catch the crew actually did not have 9 500 feet of runway to work with they only had 8 500 feet of runway when taking off from runway 0-1 right here's what actually happened the flight dispatcher talked to the tower controller the tower controller said that the runway was 9 500 feet long that is correct the entire runway is 9 500 feet long but the 747 does not have access to the first 1000 feet of that the 747 has to use a displaced threshold 1000 feet down the runway that displaced threshold is the only place from where a 747 could start its takeoff roll the tower controller assumed that the pan am dispatcher knew this and would factor it in when talking to the crew of flight 845 but he didn't i mean why would he his charts just told him that runway zero one right had 9 500 feet of usable runway and now the controller just told him the exact same thing thus the dispatcher tells the crew that they had 9 500 feet of runway at their disposal when in reality they only had 8 500 feet markings on the runway proved beyond a shadow of a doubt that they started their takeoff role from the displaced threshold you might be thinking to yourself ah so that's why this accident happened a giant jumbo jet takes off on a runway that was too short for it there's one more factor that contributed to this accident on that day the pilot started the flight under the assumption that they'd be using runway 2 8 left so they did all the preparation with runway 2 8 left's numbers they found out that runway 2 8 left wasn't available the whole discussion about what to do next took about 15 minutes and they were holding on the taxiway all that time 15 minutes of burning fuel and holding up traffic behind them this gave them a sense of urgency about the takeoff they didn't want to block traffic anymore so in their hurry they made one crucial mistake they extended their flaps from 10 degrees that was needed to take off from runway 28 left to the 20 degrees needed to take off from runway 0 1 right then they forgot to recalculate their v-speeds v-speeds are very important for takeoff v1 tells you when you can no longer safely reject a takeoff vr tells you when you can safely rotate the nose into the air and v2 is the minimum takeoff safety speed and so forth as you can tell these speeds are very important here's the thing v-speeds change when you change the configuration of the plane in this case when they decided to use flaps 20 instead of flaps 10 they should have recalculated the v-speeds but they didn't for example the rotate speed in the flaps 10 configuration is 164 knots the rotate speed in the flaps 20 configuration is 157 knots a difference of 7 knots now that seems insignificant but at takeoff speeds you'd go through 1000 feet of runway before you initiated rotation when compared to rotating at 157 knots the pilots would wait a few extra seconds to lift the nose up all the while eating through precious runway 1000 feet of runway that they just didn't have now we fully understand why this happened honestly making it off just in time isn't that rare a while back i made a video about a british airways triple seven that almost ran out of runway you can watch that video right here thank you for watching this episode of many air crash investigation if you like the videos that i make do consider liking and subscribing it will really help the channel grow i will catch you guys next time stay safe you

Channel: Mini Air Crash Investigation

Views: 234,832

Keywords: air crash investigation, air crash confidential, why planes crash, pan am, pan american, pan am flight 845, 747 crash, 747 near miss, inches from disaster, flight 845, sanfrancisco, san francisco international airport, sfo, ksfo, crash at sanfrancisco international airport, 747 accident, boeing 747, aviation documentary, mentour pilot, theflightchannel, aviation, flight simulator 2020, pan am air crash, golden age of aviation, pan am 747, aviation safety

Id: Nj7hRW-Zu2w

Length: 12min 1sec (721 seconds)

Published: Tue Oct 26 2021

Reddit Comments

[u/matt314159]

I enjoy these, thanks!

[u/SeaFailure]

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[u/WYTW0LF]

This guy’s channel is awesome. I watch several of them a day