The headline was taken from the famous aviation movie, which is also every aspiring fighter pilot’s dream flick…TOP GUN!
I am inspired to write this short commentary on the night of 5th November, 2020 due to a blast sound heard in the northern areas of Pakistan.
There has been a lot of social media frenzy, mostly from the other side of the border regarding the cause of the sound. It was rumored to be a Pakistan Air Force (PAF) fighter aircraft going down.
Pakistan’s Twitterati gave a resolute response to this onslaught by propagating their own narrative. The spill-over to televised media was also witnessed not long after the event.
Truth is far less dramatic. It is a simple case of a PAF fighter jet crossing ‘Sound Barrier’ somewhere in the north. Under prevailing external security scenario of the region, PAF has upped preparedness by pushing the throttle up a notch.
To be candid, this may as well been a ‘warning shot’ at the Indian Air Force (IAF). The latter intruded into Pakistan airspace during the skirmish of 26-27 February 2019, losing two jets in the process, one helicopter and leaving a POW behind aka ‘Nandu’. There are also reports from length and breadth of the country regarding ‘increased’ aerial activity from airbases, as well.
Coming back to the Sonic Boom business, an aircraft needs to fly at 1226 km per hour to travel faster than sound, hence named the Sound Barrier. This is also known as ‘Mach One’, after the Austrian scientist Ernst Mach. This equates to 662 knots in aviation terms. As we climb higher up in the sky, variation of air temperature, density and pressure takes place. This results into a lesser speed to attain Mach one. Direction in which nose of aircraft is pointing is also of consequence, as it dictates trajectory and travel of shock wave.
Out of experience and visiting literature, altitude of supersonic aircraft affects how far sonic booms can travel. It is dependent on width of the ‘Boom Carpet.’ Width ends up being about one mile for each 1,000 feet of altitude, so an aircraft flying at 50,000 feet would produce a sonic boom cone about 50 miles (81km) wide.
What you see above is a ‘Vapor Cone’. Normally mixed-up with breaking the sound barrier, it may or may not result from an aircraft going supersonic. A few ingredients are prerequisite for it, namely specific air pressure, temperature, humidity and density.
Interrelationship between above mentioned variables being a complicated affair, hence we will leave it for later discussion. Only this is to be understood, Mach number is not uniform over the aircraft, parts of jet may be supersonic while others remain subsonic, hence different vapor cones.
In the above tweet, are two Mirage fighter jets of PAF are shown going supersonic at Sonmiani fire power demo back in the nineties. Pardon quality of video but one can see the vapor cone generating and observe the difference in speed sound and light.
Anyways, enough said. No jets went down – only the morale of the eastern neighbor.
Sleep tight… PAF is awake!