Viscount724 From Switzerland, joined Oct 2006, 27161 posts, RR: 22 Posted (5 years 1 month 6 days 11 hours ago) and read 4386 times:
Convair 340/440s that were converted into 580s with Allison 501 turboprops are still officially designated in their type certificates as 340s or 440s, and the 580 conversion is covered by a Supplemental Type Certificate. The "580" is only an unofficial marketing designation. The same applies for the R-R Dart conversion of 240s (into 600s) and 340/440s (into 640s).
The STC covering the 580 conversion contains the following note.
Note II. Airplanes modified in accordance with this Supplemental Type Certificate are frequently referred to unofficially as "580's" or "580A's"; however, for official record purposes, these airplanes retain their original Model 340 or 440 identity.
However, DC-8-61/62/63s that were modified with CFM56 engines officially became DC-8-71/72/73s and are so identified in the main DC-8 Type Certificate Data Sheet along with all the earlier DC-8 models.
I'm just curious what would acount for the different handling of the Convair and DC-8 conversions.
411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 1, posted (5 years 1 month 6 days 7 hours ago) and read 4350 times:
The 580 conversions were completed by Pacific Airmotive in KBUR, and the FAA (at the time) wanted the original type designation to remain.
This was at the specific request of Consolidated Vultee (Convair) the original manufacturer, who still retained the type certificate.
TZTriStar500 From United States of America, joined Jan 2004, 1474 posts, RR: 8
Reply 2, posted (5 years 1 month 5 days 20 hours ago) and read 4305 times:
The reason why is the 580/600/640 STC's were performed and developed by third party companies probably without much assistance from Convair. The only way to officially change the type designation is to amend the TC and I am sure Convair was not willing to do that at the time since they still owned the TC, so those become unofficial marketing names only.
As for the DC-8-71/-72/-73 conversions, Cammacorp who developed the conversion, worked directly with McDD and it was decided to amend the DC-8 TC. I imagine it was to be able to market and support it better and maximize its market potential since McDD largely promoted it as I recall.
35 years of American Trans Air/ATA Airlines, 1973-2008. A great little airline that will not be soon forgotten.