Narrative:

At XA30 we arrived at the aircraft. We loaded crew bags and serviced the water. I left the sic and the flight attendant to prepare the cabin and preflight the plane. I then went back to the FBO; reviewed the weather and started printing the weather and flight plans. The sic called me to discuss how much fuel to put on the plane based on performance. We determined the fuel and loaded it to 20;000 pounds. I went out to the plane and the sic said the gear pins were removed; the nose pin was installed and the plane was ready. We did the before start checklist. I went back to the FBO to return the rental car and pay for our fuel bill. At XA30 the passengers started showing up. The line crew escorted them to the plane. I helped load the last arriving bags. All the passengers were on the plane. I made a quick look at the gear to ensure the pins were removed and the nose pin was in place. I normally do a walk around just to make sure nothing was left out of place. Since the passengers were onboard and I confirmed visually the pins were removed; I didn't feel I needed to walk around the plane. I then boarded and closed the door. The sic started the engines and we did the checklists and taxied out for takeoff. On initial climb out I noticed a noise. I asked the sic if he took the outflow valve cover off. He said he did not see one. I told him to keep it slow and he did. I checked the cabinet were we keep the cover and it was not there. We knew it was on the outflow valve. I had the flight attendant tell the passengers we were diverting to remove the cover. We flew at around 200 KTS. We checked and the cover was in place with no damage to the cover; the pins holding the cover and the plane. I called chief pilot; the lead captain and vp flight operations. I told the vp we diverted and landed overweight and it was a smooth landing. I checked the EICAS and it said no exceedance recorded. He called me back and said that the trip would be re-released after conferring with dispatch. We got a new release and departed. It is obvious to me that both crew members need to do their own independent preflight inspections.

Related reports:

Google
 

Original NASA ASRS Text

Title: G-IV Captain reports departing with the outflow valve cover in place after it is missed during preflight inspection. Crew diverted to remove the cover and landed overweight with no damage noted.

Narrative: At XA30 we arrived at the aircraft. We loaded crew bags and serviced the water. I left the SIC and the flight attendant to prepare the cabin and preflight the plane. I then went back to the FBO; reviewed the weather and started printing the weather and flight plans. The SIC called me to discuss how much fuel to put on the plane based on performance. We determined the fuel and loaded it to 20;000 LBS. I went out to the plane and the SIC said the gear pins were removed; the nose pin was installed and the plane was ready. We did the before start checklist. I went back to the FBO to return the rental car and pay for our fuel bill. AT XA30 the passengers started showing up. The line crew escorted them to the plane. I helped load the last arriving bags. All the passengers were on the plane. I made a quick look at the gear to ensure the pins were removed and the nose pin was in place. I normally do a walk around just to make sure nothing was left out of place. Since the passengers were onboard and I confirmed visually the pins were removed; I didn't feel I needed to walk around the plane. I then boarded and closed the door. The SIC started the engines and we did the checklists and taxied out for takeoff. On initial climb out I noticed a noise. I asked the SIC if he took the outflow valve cover off. He said he did not see one. I told him to keep it slow and he did. I checked the cabinet were we keep the cover and it was not there. We knew it was on the outflow valve. I had the Flight Attendant tell the passengers we were diverting to remove the cover. We flew at around 200 KTS. We checked and the cover was in place with no damage to the cover; the pins holding the cover and the plane. I called Chief Pilot; the lead Captain and VP Flight Operations. I told the VP we diverted and landed overweight and it was a smooth landing. I checked the EICAS and it said no exceedance recorded. He called me back and said that the trip would be re-released after conferring with Dispatch. We got a new release and departed. It is obvious to me that both crew members need to do their own independent preflight inspections.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.