PROPERTY AND EQUIPMENT

A summary of property and equipment by classification is as follows:



(In thousands)	March 31, 2017			September 30, 2016
Drilling vessels and equipment	$	3,741,648		$	3,898,686
Construction work in progress	1,011,063			857,572
Drill pipe	51,328			52,543
Office equipment and other	39,173			39,213
Total cost	4,843,212			4,848,014
Less: Accumulated depreciation	(699,822		)	(720,318		)
Property and equipment, net	$	4,143,390		$	4,127,696

Impairments

In February 2017, we agreed with Woodside Energy Ltd (“Woodside”) to (i) substitute the Atwood Condor for the Atwood Osprey, offshore Australia, for approximately 550 days starting, at the latest, March 2018 and (ii) utilize the Atwood Osprey for an additional exploration well with an estimated duration of approximately 100 days. As a result, the Atwood Condor will join the Atwood Osprey and the Atwood Eagle as one of our three rigs available to provide drilling services to clients in the Australian/Southeast Asian markets. Due to the age, specifications and marketability of the Atwood Eagle relative to the Atwood Condor and Atwood Osprey, the Atwood Eagle is positioned behind each of those two rigs to bid for contracting opportunities in the Australian/Southeast Asian markets. Based on the foregoing and our ongoing review of market conditions in the region as we continue into 2017, we determined that the Atwood Eagle is less likely to obtain future drilling contracts that would provide sufficient financial returns to justify keeping the drilling rig in a marketable condition within our existing fleet. Based on our analysis, we concluded that the Atwood Eagle and its materials and supplies were impaired as of March 31, 2017, and we wrote them down to their approximate salvage value. We recorded a non-cash impairment charge of approximately $59.0 million ($57.6 million, net of tax, or $0.74 per diluted share), which is included in Asset Impairment on the Unaudited Condensed Consolidated Statement of Operations for the three months ended March 31, 2017. This impairment charge includes a write-down of property and equipment and deferred costs of $49.6 million, a write-down of our inventory of materials and supplies that was specific to the Atwood Eagle of $8.4 million, and accrued estimated transaction costs of $1.0 million. On May 5, 2017, we executed a sale and recycling agreement with respect to the Atwood Eagle, pursuant to which the vessel, together with associated equipment and machinery will be sold to a third party to be demolished and recycled.

The Atwood Falcon completed the contract under which it was working in early March 2016. Based on the lack of contracting opportunities and the further deterioration of commodity prices, we determined that it was not likely that additional work would be obtained in the foreseeable future. Based on our analysis, we concluded that the Atwood Falcon and its materials and supplies were impaired as of December 31, 2015, and we wrote them down to their approximate salvage value. We recorded a non-cash impairment charge of approximately $64.7 million ($64.7 million net of tax, or $1.00 per diluted share), which is included in Asset Impairment on the Unaudited Condensed Consolidated Statement of Operations for the three months ended December 31, 2015. This impairment charge includes a write-down of property and equipment of $53.0 million and a write-down of our inventory of materials and supplies specific to the Atwood Falcon of $11.7 million. In April 2016, we completed the sale of the Atwood Falcon.

As of March 31, 2017, we had expended approximately $972 million towards our two ultra-deepwater drillships under construction at the Daewoo Shipbuilding and Marine Engineering Co. ("DSME") shipyard in South Korea. Remaining expected capital expenditure for these two drillships under construction totaled approximately $298 million at March 31, 2017. On December 5, 2016, we entered into supplemental agreements (collectively, "Supplemental Agreement No. 5") to the construction contracts with DSME which delay our requirements to take delivery of our two newbuild ultra-deepwater drillships, the Atwood Admiral and the Atwood Archer, by two years to September 30, 2019 and June 30, 2020, respectively. Supplemental Agreement No. 5 amends all material terms of the previous supplemental agreements. In consideration of Supplemental Agreement No. 5, we made a payment of $125 million for the Atwood Archer on December 13, 2016 and will make an additional interim payment of $15 million on the earlier of June 30, 2018 or the delivery date. With respect to the Atwood Admiral we will make a payment of $10 million on the earlier of September 30, 2017 or the delivery date. Remaining milestone payments, $83.9 million for the Atwood Admiral and $165 million for the Atwood Archer, have been extended until December 30, 2022 through our ability to choose to finance such amounts in the form of promissory notes to be entered into on the delivery dates for each vessel bearing interest at a rate of 5% per annum and to be secured by a mortgage on the respective drillship. We have the option to take earlier delivery of each vessel, upon 45 days' notice.

Other Income

During the six months ended March 31, 2016, we recognized approximately $18.0 million ($18.0 million, net of tax, or $0.28 per diluted share) of expected insurance recoveries related to cyclone damage to the Atwood Osprey. This amount is included in Other income on the Unaudited Condensed Consolidated Statement of Operations and was subsequently collected.