Tuesday was a busy day for the sales force at United Technologies (NYSE:UTX) subsidiary Sikorsky Aircraft. No sooner had the company announced the sale of "up to 26" of its new S-76D helicopters to Bristow Group (NYSE:BRS), than Sikorsky turned right around an announced another big helo sale to privately held helo lessor  Milestone Aviation -- and this one's even bigger.

According to Sikorsky, Milestone has agreed to buy 23 S-92 helicopters, as well as seven of the S-76Ds that caught Bristow's eye. In addition, Milestone is said to have taken out "options" to buy a further 14 S-92 and 10 S-76Ds at a future date. Deliveries on the initial 30-helo lot are expected to begin later this year, and continue through 2017.

How much bigger is this deal than the one inked with Bristow? No financial terms were disclosed in the announcements of either deal. That said, estimates of the usual price for the S-76D range between $9.1 million and $9.9 million. The S-92, , meanwhile, is said to cost closer to $17.7 million. This suggests the total value of Milestone's initial purchase could exceed $476 million. Add in $346.8 million in revenues if Milestone exercises all the options it took out, and Sikorsky could book in excess of $820 million on this sale.

Adding to the good news, Sikorsky announced Tuesday that it has sold a further four S-76s to the Rescue and Salvage Bureau of China's Ministry of Transport -- a deal approaching $40 million in value -- and the sum total of Tuesday's sales announcement to Bristow, Milestone, and to China, as well, could easily exceed $1.1 billion.