Narrative:

After waiting to get picked up at the terminal by the FBO; I was behind schedule for a ferry flight for routine maintenance. The weather at the destination was questionable and after looking over the aircraft MEL's; etc; my time was focused on dealing with the weather; destination approaches; etc. One of the MEL's included the upper static port plugs missing its flag. I did communicate to the first officer the many (I believe 8) small MEL's written up but I proceeded to forget about the missing flag on the static plug as I was sidetracked with the weather. After conferring with dispatch about the weather; I agreed with the dispatcher that this flight would not depart due to a blizzard forecasted for our arrival with winds favoring a runway with only a GPS approach and higher minimums that would not allow us to land. The first officer was very helpful in putting on the engine covers; pitot covers and pins; and landing gear pins. I called the assistant chief pilot about our conclusion of not departing that evening but said that the next day would possibly be a better option. No hangar was available. The next day; the first officer pulled all covers and pins while I concentrated on the weather at the destination and also the weather at the departure airport. The destination airport had the winds switched from the previous evening allowing us to do the ILS approach. The departure airport had strong winds; it was snowing and we needed to deice eventually. I did the preflight and arranged for the deicing. The ramp conditions had deteriorated with slush and was a concern. I did a quick walk around after the deicing looking over all aspects of the aircraft. Upon our flight; both of us noticed the small fluctuations between the left and right vsi and altimeters. We were in light turbulence so we chalked it up to that. Upon arrival on the ILS; we both noticed; even in strong winds that the autopilot was holding the glideslope but the indicators were fluctuating between the left and right side. I wrote up this discrepancy upon landing for maintenance to look at. I was phoned by the chief pilot of my fleet to tell me that maintenance had found the static plugs on the right side still in place; not removed and was missing its flag. This was in accordance with the MEL about one static plug flag missing. Both flight crew members missed the white static plugs against the silver background of the upper static port. According to the first officer; it is also possible that the previous crew also flew this aircraft in the same condition. A notice was sent to the flight crews today; to remind crews to write up missing flags; etc; but to not put these items on the aircraft in that condition. This certainly would have solved our problem. I will certainly look more closely at the upper static ports in the future. I am amazed that I missed this not once but twice. Once during the preflight and again in the walk around before closing the cabin door. Not to mention the first officer also missed seeing the plugs were still in place. This certainly isn't the first officer's fault; as it was my responsibility for the preflight. It is just an observation that it was apparently very easy to miss static plugs still in place with flags missing.

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Original NASA ASRS Text

Title: HS125 Captain reports over looking a static port cover with it's flag missing; during preflight. In flight this causes small fluctuations between left and right airspeed and vertical speed indicators. The company changes procedures to not permit crews to install covers with missing flags.

Narrative: After waiting to get picked up at the terminal by the FBO; I was behind schedule for a ferry flight for routine maintenance. The weather at the destination was questionable and after looking over the aircraft MEL's; etc; my time was focused on dealing with the weather; destination approaches; etc. One of the MEL's included the upper static port plugs missing its flag. I did communicate to the First Officer the many (I believe 8) small MEL's written up but I proceeded to forget about the missing flag on the static plug as I was sidetracked with the weather. After conferring with Dispatch about the weather; I agreed with the Dispatcher that this flight would not depart due to a blizzard forecasted for our arrival with winds favoring a runway with only a GPS approach and higher minimums that would not allow us to land. The First Officer was very helpful in putting on the engine covers; pitot covers and pins; and landing gear pins. I called the Assistant Chief Pilot about our conclusion of not departing that evening but said that the next day would possibly be a better option. No hangar was available. The next day; the First Officer pulled all covers and pins while I concentrated on the weather at the destination and also the weather at the departure airport. The destination airport had the winds switched from the previous evening allowing us to do the ILS approach. The departure airport had strong winds; it was snowing and we needed to deice eventually. I did the preflight and arranged for the deicing. The ramp conditions had deteriorated with slush and was a concern. I did a quick walk around after the deicing looking over all aspects of the aircraft. Upon our flight; both of us noticed the small fluctuations between the left and right VSI and altimeters. We were in light turbulence so we chalked it up to that. Upon arrival on the ILS; we both noticed; even in strong winds that the autopilot was holding the glideslope but the indicators were fluctuating between the left and right side. I wrote up this discrepancy upon landing for maintenance to look at. I was phoned by the Chief Pilot of my fleet to tell me that Maintenance had found the static plugs on the right side still in place; not removed and was missing its flag. This was in accordance with the MEL about one static plug flag missing. Both Flight Crew members missed the white static plugs against the silver background of the upper static port. According to the First Officer; it is also possible that the previous Crew also flew this aircraft in the same condition. A notice was sent to the Flight Crews today; to remind Crews to write up missing flags; etc; but to NOT put these items on the aircraft in that condition. This certainly would have solved our problem. I will certainly look more closely at the upper static ports in the future. I am amazed that I missed this not once but twice. Once during the preflight and again in the walk around before closing the cabin door. Not to mention the First Officer also missed seeing the plugs were still in place. This certainly isn't the First Officer's fault; as it was my responsibility for the preflight. It is just an observation that it was apparently very easy to miss static plugs still in place with flags missing.

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.