Date: 201705
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Parked
ATC / advisory: Ramp ZZZ
Aircraft component: Pitot/Static Ice System
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Troubleshooting
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew; Person Ground Personnel
When detected: Pre-flight
Result: Flight Crew Took Evasive Action; General Maintenance Action
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: Ferry flight. During the exterior inspection; two ramp personnel on a golf cart drove up to me and urgently got my attention to point out covers over the rudder feel differential pressure pitot probes. I had not reached the tail and was just at the tip of the right wing when they alerted me to the problem. To save time; I asked them to radio for a technician to come out.The aircraft was pulled from the hangar to perform the flight and had a valid Maintenance release (issued a few minutes before my arrival) when I got to the aircraft.It was around noon on a bright; sunny; day while I was doing my preflight. I am not certain that I would have noticed the tube covers from my vantage point low and alongside the tail while performing my routine inspection. The glare of the sun made it very difficult to look up and see the covers. Further; the red 'remove before flight' streamers were intermittently wrapping around the pitot tubes because of the wind.I am very thankful that the lead ramp agent and his coworker were vigilant. It was easier to see the covers from afar when approaching the aircraft. The ramp lead was training a group of new hire ramp personnel and brought them to the back of the aircraft to show them the problem. He asked me to come over and explain to the new hires what was wrong and why it was important. I was extremely impressed with the lead's effort to make this a learning experience for his team!After returning to the flight deck; I called maintenance on the radio and asked if they were going to send a new release form (presumably writing up the mistake). The radio operator seemed confused and insisted that our existing release form was valid since a tech came out and removed the pitot tube covers. This seems suspicious to me - the presence of pitot covers on an already released airplane should have been cause for a new logbook entry. We ultimately went with the hub maintenance suggestion and departed without a new log entry.




Synopsis: B737 First Officer reported during preflight an aircraft just returned from the hangar; ground personnel notified him about pitot covers not removed from the RUDDER FEEL DIFFERENTIAL PITOT tubes. The pilot stated he may never have seen them from his vantage point.