Who's Online

We have 1530 guests online

Live Traffic Feed

Life in the Skies

'A Local Bestseller!'

What Tony says
(See here)
and Book Launch video here
 
What others say

Les Posen
(See
here)

Yvonne Lee
(See
here)

Louisa Lim & Allan Koay
(See
here)

Aireen Omar, Asran & Bo Lingam
(See
here)

38 Readers' Comments
(See here)

Get an autographed copy here

AMAZON.COM  -  To Order, please Click here 

(eBook) Kindle edition - please Click here

Latest Comment

Does a jet aircraft
There is almost no curvature, because the Earth is

Does an airline capt
I dont think the interview on our side (nautical)

A successful SIA Cad
I am a 3rd year student in Singapore polytechnic.

Cadet Pilots and Pil
captain how to in to the pilot career, becausee i

The twin-engine vers
Dave, in short, it depends on the severity of the

Engine Failure of QA
I heard the Captain of that flight was undergoing

What are the eyesigh
Sir, I am interested to become an airline pilot! T

My Boyfriend is Deat
4 engines plane more safe, remmember passenger pla

Eyesight requirement
HELLO SIR; I have a specks of 1.0 no. so can i eli

Cadet Pilots and Pil
hi capt lim, i want to know that does the cadet pi

Paperback Version

 For Local Availability - Check Here
 
Home > Flying the Plane > How far can a Boeing 747 glide with all engines failed?
How far can a Boeing 747 glide with all engines failed?
Flying - Flying the Plane
Sunday, 21 October 2012 14:57

BA 009 Volcanic Ash Flight

Hi Capt Lim,

Can you please provide me with information about the B747-400ER optimal glide ratio?

Looking through the web I came up with figures ranging from 1:9 to 1:22...

How much better is it compared to the B747-200 (I think it has 1:15)?

Thank you.

Tsahi

Hi Tsahi

To the aviators, glide ratio information is generally not given or found in the Flight Manuals as the pilot usually flies the correct airspeed to get the optimal glide in the event of all engine failures. What is available to the pilots are the best gliding speed (best lift/drag ratio) at different weight and altitude.

However as a rule of thumb, most modern jets have an average glide ratio of around 1: 15 - meaning for every 15 feet forward, it drops one foot.

For instance, on an Airbus A330, assuming all engines failed at 40,000 feet, the recommended initial speed to fly at is 300 knots to achieve an auto restart. If all fails, the speed would be reduced to the best gliding speed (green dot speed) of approximately 210 knots at 180 tons. Just before touch down, speeds are further reduced as the landing gears and flaps are selected.

So the initial glide ratio is 1:18 (approximately 1300 feet per minute or covering 3 nm for every 1000 feet) reducing to a glide ratio of 1:9 (1.5 nm for every 1000 feet) on the landing approach.

Overall, at an average glide ratio of 1:15, the plane would glide a distance of around 100 nautical miles with nil wind from 40,000 feet.

Similarly, the Boeing 747-200 and 747-400ER should also be the same and have an average glide ratio of around 1:15.

PS. To check for any latest updates or postings, you can follow my new Twitter at @CaptKHLim


Boeing 747 - Falling from the Sky


Boeing 767 – The Gimli Glider


A330 – Flying on Empty

Trackback(0)

TrackBack URI for this entry

Comments (1)

Subscribe to this comment's feed
...
So there's lecture on stability on, so does moving all the passengers to the front of plane create stability?
David , 27 Mar, 2016

Write comment

smaller | bigger

busy
 

Paperback Version

 For Local Availability - Check Here

Recommended By..


LIFE IN THE SKIES

'A Local Bestseller!'

Recommended by

Patrick Smith
Boston USA
(See
here)

Capt Meryl Getline
ex-United Airlines USA
(See
here)

Capt Doug Morris
Canadian Airlines
(See
here)

Capt  Robert J Boser
ex-United Airlines USA
(See
here)

38 Readers' Comments
(See here)

Get an autographed copy here

AMAZON.COM  -  To Order, please Click here 

(eBook) Kindle edition - please Click here

View Book Launch video here

Follow me

@CaptKHLim

Like What You Read?


If you like what you read, more stories are found in my book LIFE IN THE SKIES (Preview here) and you can purchase a copy here. To check for any latest updates or postings, you can follow my Twitter at @CaptKHLim or Facebook here

MH 370 Interviews

Click here to View

10 Most Popular Posts



Disclaimer | Privacy
2004 - 2011 © AskCaptainLim.com | Site Concept by eQuilec.com