9 December – air assault It had become clear to Gen. Sagat Singh by 7 December, that an air assault operation would be required to cross the Meghna. Inspired by the airlift/air assault operations that had surrounded Sylhet between 6 and 9 December, he ordered plans to be drawn up for a similar operation to cross the Meghna. The engineers of 15 Engineer Regiment and Group Captain Chandan began to plan the operation. They identified possible landing grounds and, with the help of the
Mukti Bahini, began to mark them with modified torches. Mukti Bahini fighters set up these modified torches in paddy fields at Raipura (the DZ) in the hours before the helicopters landed. At 1300hrs on the 9th, as 18 Rajpur and 10 Bihar entered Ashuganj, 4 Guards was recalled from the lines at Ashuganj to the
stadium at Brahmanbaria. Sometime in the evening, they began to board Mi-4 helicopters bound for Raipura. According to Major Chandrakant Singh, an officer in 4 Guards at the time, the 14 Mi-4s were escorted by 2
Folland Gnat fighters and landed at their DZ without any issue. The Mi-4s had had to land, in the pitch dark, on dimly lit fields. As such, upon landing,
Flying Officer D. S. Shaheed got out and began to mark the DZ with wheat flour. At the time, there was a fear that the two brigades of the Pakistani 14th Inf Div at Bhairab Bazar would spot the landings and overwhelm 4 Guards before they'd had a chance to regroup. However, no such counterattack materialised. By 4 am, the helicopters had conducted about 50-60 sorties and had moved all ~700 men of 4 Guards, along with an artillery battery from 82 Light Regiment, to Raipura. After the war, it was revealed by Pakistani POWs that – upon hearing the sound of helicopters – it was assumed that an entire Indian brigade had been landed to their rear and as such, they were not allowed to move out of Bhairab Bazar.
9 December – 19 Punjab crosses the Meghna At the same time as 4 Guard was moving, 19 Punjab had moved further south on the eastern bank of the Meghna to the village of Charlalpur. From here, using commandeered civilian
fishing boats, they crossed the Meghna under cover of darkness, with the entire battalion having crossed within a few hours. They immediately moved to surround the Pakistani forces at Bhairab Bazar, as there were fears of an imminent Pakistani attack on 4 Guards.
10–11 December – advance on Narsingdi 4 Guards had reorganised and regrouped by 0400hrs, following the landings at Raipura. After patrols had scouted out Pakistani positions on the road to Narsingdi, 4 Guards began their attack on Narsingdi railway bridge. Their objective was to keep the Pakistani defenders occupied and unable to detonate the explosives on the bridge. By the end of the day, the battalion had secured a river crossing point on the western bank of the Meghna and had captured the railway bridge at Narsingdi. It materialised that the Pakistanis had left behind only 1 platoon of paramilitary to defend Narsingdi, with the Army moving across the
Lakhya River to bolster the defence of Dhaka. As such, 4 Guards faced no casualties and wiped out or captured the platoon with ease. As 4 Guards was fighting in Narsingdi, the Mi-4s were carrying out multiple sorties to land 10 Bihar at Raipura. From there, 10 Bihar (along with a battery of medium artillery which was also landed) moved west to assist in the capture of Narsingdi. Simultaneously, on the 11th, 19 Raj Rif had been crossing the Meghna on boats and linked up with 4 Guards by midday, being transferred into 311 Mountain Brigade.
12 December – advance towards Dhaka With 27 and 313 Infantry Brigades successfully isolated at Bhairab Bazar, the entirety of 311 Mountain Brigade would be airlifted into Raipura by the 14 Mi-4s which flew over 200 sorties between 9 and 13 December. By 0800hrs, 4 Guards – the forwardmost unit of 311 Mountain Brigade – was only 12 kilometers short of Dhaka. They encountered Pakistani positions on the east of the Lakhya River, but these were quickly overwhelmed. By the end of the 12th, 311 Mountain Brigade was within artillery range of Dhaka. == Aftermath ==