Interesting update on 747SP last seen at YQT - now at MTJ

Member for

14 years 7 months

Posts: 91

The story so far: http://www.747sp.com/NewsDetail.asp?id=32 Not that interesting? Well how about the fact that this aircraft is the famous "Dive Queen" as reported in this months Air and Space Magazine. This aircraft has been moved to Tijuana Mexico and is reported as sitting around without much work being done to it. It seems that this aircraft, N4522V is an ex-China Airlines aircraft that on Feb 19, 1985 made a dive from 41K down to 9.5K and during the pull out reached 5.1 G's :eek: which ripped the Aux power unit from it's mounts and put a 2 inch "set" in the wing dihedral. There were only minor injuries reported to pax after it landed in San Francisco. You've seen us drive - now watch us fly mode! NTSB Report HTML http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001214X35672&key=1 PDF Format http://www.ntsb.gov/ntsb/GenPDF.asp?id=DCA85AA015&rpt=fi China Airlines colours http://www.geocities.com/TheTropics/1145/N4522V-001LTR.jpg Current colours http://www.hamaerotech.com/Gallery/Other/GPI_N4522V_Sized.jpg History of aircraft http://www.747sp.com/History.asp?22805
Original post
Profile picture for user Bmused55

Member for

16 years

Posts: 10,625

Interesting indeed! So if I understand this correctly, this SP's wings angle up higher than the standard SP? IE, the wing tips are higher off the ground. All because of the G forces involved in the recovery from the dive. Shows ya how sturdy the 747 is.

Member for

19 years 9 months

Posts: 2,228

the structure is plastically deformed due to the overall wing bending moment in the pull-out and as such the wing structure will never return to its original state, as would happen under elastic conditions. It shows you that all aircraft will perform beyond their design criteria, but with certain side effects. The 747 is not just an exception to the rule, its just how we design for the materials available.

Member for

16 years 5 months

Posts: 12,842

the structure is plastically deformed due to the overall wing bending moment in the pull-out and as such the wing structure will never return to its original state, as would happen under elastic conditions..
With the wings in that state, wouldn't that make it unfit to fly
Profile picture for user symon

Member for

14 years

Posts: 992

yeah.....im not totally sure they would let it fly once past its elastic limit. if it went plastic it would not only change the aerodynamics of the wing profile, it would also highly increase the chance of the wings yielding under the stress it is exhibited to. perhaps after thorough investigation they concluded they wings were still within the elastic region after the incident OR they were not far into the plastic region to be any great concern (contradictory to the above i know, but im no expert (yet ;)))

Member for

19 years 9 months

Posts: 2,228

indeed, you can not be in both the plastic and elastic regions of the stress/strain curve! Once somthing has been stretched (convert this into strain) above the elastic limit of the material it will never return to its original shpe and size. Worth noting that the wing is probably still capable of carrying the design criteria. I would think that this event has shortened the fatigue life of the aircraft by some amount. If there was no structural failure, or adequate repairs could be made to the structure, there would be no need to take the aircraft off the line.