Can't help with the 'when', but here's some 'what' -- found in the 3/31/07 SEC 10-Q filing:
...edgar-online.com/fetchFilingFrameset.aspx?FilingID=5168570
Note 10 Fleet Information and Commitments
As shown in the following table, Northwest operated a fleet of 375 aircraft at March 31, 2007, consisting of 317 narrow-body and 58 wide-body aircraft. Northwests purchase commitments for aircraft as of March 31, 2007 are also provided
Code:
---In Service------------- Aircraft
Seating Capital Operating on Firm
Capacity Owned Lease Lease Total Order
Airbus:
A319 124 64 1 65 5
A320 148 45 28 73 2
A330-200 243 11 11
A330-300 298 15 15 6
Boeing:
787-8 221 18
757-200 180-184 38 1 16 55
757-300 224 16 16
747-200 353-430 2 1 3
747-400 403 4 12 16
McDonnell Douglas:
DC9 100-125 108 108
------------------------------------
303 1 58 362 31
Freighter Aircraft
Boeing 747F 10 3 13(1)
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Total Northwest Operated Aircraft 313 1 61 375 31
Regional Aircraft
CRJ200 44-50 140 140
Saab 340 30-34 49 49
CRJ900 76 36
Embraer 175 76 36
Total Airlink Operated Aircraft 189 189 72
------------------------------------
Total Aircraft 313 1 250 564 103
.
(1) On February 2, 2007, one Boeing 747F aircraft was removed from scheduled service, and the Company intends to remove an additional Boeing 747F aircraft from scheduled service during the remainder of 2007.
The Company took delivery of two Airbus A330-300 aircraft during the three months ended March 31, 2007. In connection with the acquisition of these aircraft, the Company entered into long-term debt arrangements. Under such arrangements, the aggregate amount of debt incurred totaled $167 million.
Note 11 Aircraft Impairments
In the first quarter of 2007, the Company recorded $13.3 million related to the impairment of three owned aircraft, which were permanently removed from service. These charges reflect the Companys decision to park three DC9-30 aircraft permanently, consistent with the Companys ongoing review of its aircraft fleet plan in conjunction with its overall route structure and capacity requirements. The first quarter 2007 impairment charges were recorded as reorganization expenses.
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