Who's Online

We have 1678 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 > Does sonic booms arise from a strong tail wind?
Does sonic booms arise from a strong tail wind?
Flying - Flying the Plane
Saturday, 17 March 2012 00:59

Supersonic Flight, Sonic Booms
 
Hi Capt Lim,

A Boeing 777 cruising at 450 knots is being blown by a jet stream of 180 knots; the resultant ground speed is 630 knots (450 + 180). This is 48 knots (630 - 582) greater than the speed of sound at 12000 meters...

Does the sonic boom reach the ground? Does the pilot have to throttle back to avoid this?

Lee Ferguson,

Hi Ferguson,

I wrote about this in the Travel 3Sixty magazine here under the heading, 'From Subsonic to Supersonic'

Passengers have often asked me if an aircraft encounters a strong tail wind in a jet stream, can it break the sound barrier.

The answer is ‘No’. Airbus and Boeing planes flying currently are all subsonic planes. It means they are designed to fly below the speed of sound. Even if there is a strong tail wind pushing the plane forward and the ground speed has exceeded the theoretical speed of sound - in reality, the plane has not gone supersonic.

This confusion arises from the misunderstanding of ground speed and the plane’s speed. Ground speed is the speed at which an object travels relative to a fixed point on the Earth’s surface. The difference between ground speed and airspeed is caused by the influence of winds on the overall speed of the aircraft.

For example, if you were walking at a speed of 2 mph on a moving walkway (walkalator or travelator), which is also moving at 2 mph, your actual speed as observed by a person NOT on the moving walkway would be fairly speedy – 4 mph (2 + 2). However, as far as you are concerned, you are still walking at 2 mph!

So the question of sonic boom does not arise and the pilot need not have to throttle back! Hope that answers your question.

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


Ground Speed Versus Airspeed


Sonic Boom


Trackback(0)

TrackBack URI for this entry

Comments (0)

Subscribe to this comment's feed

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