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B737-800 flight crew reported returning to the departure airport after noting the captain's side airspeed and altimeter were unreliable.
| Attributes | |
| ACN | 1354730 |
| Time | |
| Date | 201604 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Takeoff |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Airspeed Indicator |
| Person 1 | |
| Function | Captain Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | Pilot Not Flying First Officer |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Speed All Types |
Narrative:
On takeoff the first officer stated 'airspeed' at 100kts. Decision was made to continue. During the climb captain's airspeed accelerated to 380-420 kts. First officer's airspeed was normal. Passing through 6;000 feet the clacker came on. The first officer went through the unreliable airspeed check list [and] altimeter disagree checklist. We transferred controls and contacted maintenance and dispatch. Suggestion was made to activate the stall protection system test to get the clacker off. This did not work. After determining the first officer's information was accurate the first officer flew the airplane. At one point ATC was showing that the captain's data was correct. The first officer pointed to the standby information and we switched to number two transponder. This gave ATC accurate information. We planned a 15 mile final and configured early. The clacker went off while descending through 6;000 feet. We selected flaps 30 and the flaps indicator showed 25 based on captain's information. We selected 40 and the indicator went to 30 as we were on short final we selected flaps 30 and flaps stayed at 30. Captain's airspeed slowed to about 120 as the plane approached to land.
Original NASA ASRS Text
Title: B737-800 flight crew reported returning to the departure airport after noting the Captain's side airspeed and altimeter were unreliable.
Narrative: On takeoff the First Officer stated 'airspeed' at 100kts. Decision was made to continue. During the climb Captain's airspeed accelerated to 380-420 kts. First Officer's airspeed was normal. Passing through 6;000 feet the clacker came on. The First Officer went through the unreliable airspeed check list [and] altimeter disagree checklist. We transferred controls and contacted Maintenance and Dispatch. Suggestion was made to activate the stall protection system test to get the clacker off. This did not work. After determining the First Officer's information was accurate the First Officer flew the airplane. At one point ATC was showing that the Captain's data was correct. The First Officer pointed to the standby information and we switched to number two transponder. This gave ATC accurate information. We planned a 15 mile final and configured early. The clacker went off while descending through 6;000 feet. We selected flaps 30 and the flaps indicator showed 25 based on Captain's information. We selected 40 and the indicator went to 30 as we were on short final we selected flaps 30 and flaps stayed at 30. Captain's airspeed slowed to about 120 as the plane approached to land.
Data retrieved from NASA's ASRS site 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.