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MD82 flight crew reported unreliable airspeed indications during descent from FL330. Both primary pitot systems showed signs of icing as airspeed decreased with altitude and showed 235 knots while the standby showed 310 knots. After descending out of IMC; airspeed indications returned to normal.
| Attributes | |
| ACN | 1338556 |
| Time | |
| Date | 201603 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | US |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | MD-82 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Descent |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Pitot-Static System |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | Pilot Flying First Officer |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Total 15000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Inflight Event / Encounter Weather / Turbulence |
Narrative:
Started getting moderate turbulence at FL330. Asked ATC for FL240 since we were approaching TOD. First officer started a gradual descent and noticed that the airspeed was slowly decreasing so first officer increased the vertical speed down. We cross checked the air speeds and mine was the same as first officer's; 235 KIAS and decreasing. Aircraft started a buffet much like the speedbrakes were extended so I cross checked standby airspeed indicator and it read 310 KIAS (actually approaching an over speed). First officer decreased the vertical speed. We decided to run the airspeed unreliable quick action checklist. First officer turned autopilot; auto throttle; and FD off. I checked meter sel and heat switch not off. We decided both primary airspeed indicators were faulty. First officer transferred control of aircraft to me so I could fly by standby airspeed indicator. First officer asked for descent to 10;000 feet. Contacted dispatch; informed flight attendant's; and briefed passenger. ATC cleared us direct to the airport. Several minutes after attaining VMC the primary instruments started to return to normal parameters. Landed without further problems.fix the airplane. It had numerous write ups.
Original NASA ASRS Text
Title: MD82 flight crew reported unreliable airspeed indications during descent from FL330. Both primary pitot systems showed signs of icing as airspeed decreased with altitude and showed 235 knots while the standby showed 310 knots. After descending out of IMC; airspeed indications returned to normal.
Narrative: Started getting moderate turbulence at FL330. Asked ATC for FL240 since we were approaching TOD. FO started a gradual descent and noticed that the airspeed was slowly decreasing so FO increased the vertical speed down. We cross checked the air speeds and mine was the same as FO's; 235 KIAS and decreasing. Aircraft started a buffet much like the speedbrakes were extended so I cross checked standby airspeed indicator and it read 310 KIAS (actually approaching an over speed). FO decreased the vertical speed. We decided to run the Airspeed Unreliable Quick Action checklist. FO turned autopilot; auto throttle; and FD off. I checked Meter SEL and Heat switch not off. We decided both primary airspeed indicators were faulty. FO transferred control of aircraft to me so I could fly by standby airspeed indicator. FO asked for descent to 10;000 feet. Contacted dispatch; informed FA's; and briefed PAX. ATC cleared us direct to the airport. Several minutes after attaining VMC the primary instruments started to return to normal parameters. Landed without further problems.Fix the airplane. It had numerous write ups.
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.