From kls Mon Feb 3 03:16:35 1997 Newsgroups: sci.aeronautics.airliners Path: bounce-back Date: 03 Feb 97 03:16:35 From: rickydik@ix.netcom.com (RD Rick) Subject: Re: DC-8s in service; no 707s? References: Message-ID: Approved: kls@ohare.Chicago.COM Sender: kls@ohare.Chicago.COM Organization: Netcom In National Aero Safety writes: >Louis A. Ramsay wrote: >> In "Richard Isakson" >> writes: >> >> Is there a reason that the DC-8 airframes are still in service >> >> up to 30 years later while the 707s are not? >Isn't it also a factor that the Douglas DC-8's being the superior >product, are less prone to corrosion that the Draconian Boeing 707's? >All kidding aside, it is my understanding that Douglas put more effort >into corrosion protection. The DC-8 is also a newer design. My first DC-8 ride was in 1959. The 707 wasn't all that much earlier. I remember being told years ago that the 707 wing is prone to cracking, and good for only about 30,000 hours, while the DC-8 is overbuilt, and many have exceeded 100,000 hours. When UPS was in the midst of buying re-engined DC-8's, they looked at what it would take to fly them for another 20 years. They modernized the avionics. They also certified and installed a new autopilot - unprecedented in a transport category jet. It doesn't make sense to re-engine a plane with limited hours life - unless you are the USAF, with limited utilization. WRT DC8-70 series, I believe it is the CFM-34, and not CFM-56. RD