Team-BHP - Loud boom noise in Bangalore

Quote:

Originally Posted by AirbusCapt (Post 4808739)

No. It's illegal to fly supersonic over indian airspace. However I'm not sure if the armed forces are subject to this regulation.

India is steadily introducing noise abatement regulations for commercial and private aircraft. So far, military aircraft are exempt from these regulations.

That said, this is just nuts. Sonic booms over metro areas aren't fun. They cause damage. My home is on the landing approach to HAL airport. We are subjected to really loud noises 3-4 times a day (not to mention the occasional IL-76 that lands after midnight). When HAL was built, it was outside the city, but this airport is now smack dab in the middle of the city. Considering how much this land is worth, they can happily find a location on the coast where they can test their jets over water without spending an extra penny.

I completely understand forward military bases that maintain an active defensive posture (Bhuj, Jaisalmer etc.). Bangalore is nowhere near there.

I used to live in Chicago and they had a naval air station in a nearby town called Glenview. As Chicago started expanding, they closed the air station and moved it to a place further away on the shores of Lake Michigan (that means access to airspace over water).

Well I too heard it in J P Nagar 2nd phase at about 1:20 PM. I got a whatsapp forward in a group by PRO Bengaluru which states "that it was a routine IAF Test Flight involving a supersonic profile which took off from Bluru Airport and flew in the allotted airspace outside city limits. The aircraft belonged to ASTE. The sonic boom was probably heard while the aircraft was decelerating from supersonic to subsonic speed between 36000 and 40000 feet altitude." I have not verified the authenticity of this message.

Quote:

Originally Posted by poloman (Post 4808880)

People are mistaking sonic boom to jet roar. These are totally different. You can see the similarities between bangalore bang and recorded sonic booms from jets....

The second video is not just simple jet roar. It is a sonic boom caused by supersonic fighter jets. We keep hearing it in Pune regularly.

What you hear in the first video appears to be artillery explosions because a sonic boom doesn't end abruptly.

The second video is a mix of both. The flights seen around 0.32s and 1.35s generated what is the closest to the sound we heard in Bangalore.

I am not sure about the source of Bangalore video. But this is what I heard and experienced personally near Whitefield.

I think the jet was flying high, so we did not hear the roar clearly.

Quote:

Originally Posted by balenoed_ (Post 4808978)

Sorry, please elaborate this. Is this part of the sonic boom/Jet or is it a different subject all together.

All "booms" happen due to supersonic motion.
1) Crack of the whip in air is the smallest "boom" that you hear because the tip of whip is moving at supersonic speed.

2) The roar of jet engine you hear is because of supersonic speed of turbine blades and exhaust gases.

3) Afterburners (introducing the jet fuels after the turbines) cause even higher quantity and velocity of supersonic gases - hence louder roar.

4) Explosion (like artillery round, bomb, gunshot) are booms caused by sudden expansion of gases formed by rapid combustion.

5) A fighter plane (or Concorde also in past) sonic boom is caused by such a large body moving at supersonic speed.

All I am saying is that fighter plane boom doesn't die out abruptly (you keep hearing rumbling white noise for a long duration with decaying intensity). Whereas the bomb explosion dies out abruptly. The first video sounds more like a bomb blast rather than fighter plane.

Quote:

Originally Posted by alpha1 (Post 4808992)

The first video sounds more like a bomb blast rather than fighter plane.

Since it was heard in most parts of the City, if it was an explosion, wherever it happened, people in that vicinity would have lost their hearing. Unless such an explosion has happened in the middle of nowhere, where nobody lives. Such places do not exist in Bangalore. Or does it?

Defence ministry has accepted it was the IAF aircraft from ASTE that caused it.

Although the boom is continuous as long as it keeps travelling at above the speed, the sound is heard when the cone passes the observer. I think the sound is not really long drawn and is brief as in videos above.

This sound also felt more amplified probably because the urban centres aren't producing their usual levels of sound pollution. Things are still relatively quiet, inspite of Lockdown-4. So imagine if this happened in the peak lockdown period in the evening or something. But yes, all glory to the men in their magnificent flying machines !

Quote:

Originally Posted by srini1785 (Post 4808243)

They have started BMTC bus service in bangalore and the noise was that of BMTC bus going supersonic in the wide open roads. :)

I heard it too at Banerughatta. I doubt the HAL Jet theory.

I do not know which one has a higher chance of happening !!

Empty roads in Bangalore??

BMTC busses crossing 50 kmph??

Who knows? :uncontrol