AeroTech I225FJ (RMS-38/480, in 38/600 casing with RAS), dual-deploy (no motor eject). First flight of rocket in "mk V" configuration, after re-build from previous failure and restoration of rocket to Dual-Deploy configuration. Full video from countdown to landing, altimeter did not beep on landing for unknown reasons. This flight was meant to be an "in-air test" of shear pinning due to inability to ground-test, this was my first use of shear pins in a dual-deploy rocket instead of simple friction-fitting. In order to ensure soft landing both the lower and upper airframe sections were packed with 36" main parachutes, on assumption that second ejection event may fail to shear pins. While the apogee charge fired as expected, the 36" parachute failed to be pulled out of the drogue bay, causing rocket to descend fast. Rocket speed around 133 mph when second charge fired at 700 feet, sudden deceleration resulted in significant zipper to lower airframe, newly-replaced airframe section completely destroyed. Upper airframe and remainder of lower airframe undamaged, landing occurred at a safe speed due to both 36" parachutes being deployed before landing. The rocket will be able to fly again once damaged airframe section is replaced, or rocket is converted back to single-deploy by permanently attaching upper airframe section to lower airframe. StratoLogger CF (SLCF) and AltimeterThree (A3) altimeters flown with data downloads. Altimeter logs (with video correlation): Altitude: SLCF: 1810 ft, A3: 1816 ft Top Speed: SLCF: 304 mph Thrust Time: Video: ~1.57 s Coast-Apog: Video: 9.03 s Descent: SLCF: 16.6 ft/s (11.4 mph) Duration: SLCF: 48.5 s, A3: 49.5 s, Video: 47.3 s Landed approximately 435 feet from launch pad. OpenRocket simulation suggested: Altitude: 1924 ft Top Speed: 247 mph Max Accel: 9.37 G Apogee @ 11.2 s (9.5 s optimum delay) Descent: 20.4 mph (single 36" parachute), 14.4 mph (both 36" parachutes) Duration: 75.7 s (single 36" parachute), 85 s (both 36" parachutes)