An HS-125-800XPC crew reported that during the early morning preflight the Captain tried to pull the right pitot tube cover off but only the cover's flag was removed. In flight an airspeed discrepancy was noted but the pitot cover was not discovered until they reached their destination.
Synopsis
An HS-125-800XPC crew reported that during the early morning preflight the Captain tried to pull the right pitot tube cover off but only the cover's flag was removed. In flight an airspeed discrepancy was noted but the pitot cover was not discovered until they reached their destination.
Narrative
We showed at XA:00 local; I did a preflight; which included removing all pins and pitot covers. We fueled; and I did another walk around; looking for anything abnormal; such as flags; unlocked panels or bent metal. When the passengers arrived I did another final walk around before takeoff. I was the flying pilot in the left seat; and after the normal takeoff I was told of an airspeed anomaly on the copilot's side. I continued to fly to a safe altitude; whence the First Officer went through the checklist for his airspeed malfunction. We complied with the checklist; and were aware of any system degradation. As we reached a higher altitude; we called the Company and informed the Assistant Chief Pilot of the situation. He agreed that the weather was clear the entire route; our fuel was sufficient; and we could proceed to our destination safely if we were comfortable. We continued and checked our FOM to make sure we were complying with all limitations. The trip was uneventful; and we landed safely with no further note. During postflight it was found that when I pulled the pitot cover off from the copilot's side; the string attaching the flag to the rubber cover broke; so that in my hand was only the flag and not the pitot cover. When I stowed the flag along with the rest of the covers; I missed that the pitot cover had broken and was still on the pitot tube. On my subsequent walk arounds I missed this broken cover; because it was still dark; the cover is small and black; and I was looking for flags and other obvious missed items. Removing the pitot cover by the grabbing the rubber part would ensure proper removal; along with touching each pitot to verify that it is indeed clear. A stronger attachment between the flag and the pitot would also be good; to ensure it does not break so easily. Also; during a night pre-flight; extra care must be taken to ensure everything is as should be.
Second reporter narrative
On takeoff; I observed an airspeed discrepancy between the three airspeed indicators shortly after 80 KTS. I notified the pilot flying after rotation and in a stabilized climb. We continued the climb to a safe altitude utilizing the left pilot's instruments. After completing the checklist; we ascertained that we had an ADC fault of the right pilot's instruments. We contacted the Assistant Chief Pilot via phone and discussed the weather en route and at the destination; fuel status and applicable aircraft systems affected. We agreed that a safe flight to the destination could be achieved; and it was. Upon post flight inspection; the rubber cap that protects the right pitot tube was still attached. Utilizing the red 'slip on' pitot covers that are attached to the AOA Vane strap on all the aircraft might make the pitot covers more visible than the black rubber caps used on others on night inspections.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.