 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
TBM7 pilot reported an altitude deviation resulted from a pitot static system anomaly.
| Attributes | |
| ACN | 1478003 |
| Time | |
| Date | 201708 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | PDK.Airport |
| State Reference | GA |
| Environment | |
| Flight Conditions | IMC |
| Light | Dawn |
| Aircraft 1 | |
| Make Model Name | TBM 700/TBM 850 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | Climb |
| Route In Use | Vectors |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Pitot-Static System |
| Person 1 | |
| Function | Single Pilot |
| Qualification | Flight Crew Commercial Flight Crew Instrument |
| Experience | Flight Crew Last 90 Days 20 Flight Crew Total 1000 Flight Crew Type 700 |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Altitude Overshoot Deviation - Procedural Clearance |
Narrative:
On climb out in hard IMC/turbulence/rain I had a complete airspeed indicator failure on pilot side. I misdiagnosed this as a pitot failure (since glass instruments were still reporting altitude and the indication 'seemed to make sense' for stage of climb out) and began to operate off copilot airspeed but otherwise pilot side instruments for altitude and heading. Autopilot kicked off when airspeed on G600 failed. Unfortunately it was still reporting altitude and I believed what I saw. I leveled on heading 270 at indicated 5;000 feet and began to diagnose/debug. Checked pitot heat; checked power settings; etc. While hand-flying to maintain altitude [and] heading. High workload environment to say the least. After several other steps; I pulled the alternate static - immediately restored airspeed indicator on pilot side but; to my surprise; altitude also immediately wound up to approximately 7;500-8;000 feet. Apparently it was not a pitot tube problem but a static problem. I cross checked to GPS altitude and began correcting; while hand-flying and maintaining 270. ATC no doubt saw same as me - a near instantaneous altitude gain of 2;500-3;000 feet - and contacted me for an immediate course change to 360. I complied and we worked together to get back to assigned altitude.learnings: cross check constantly in IMC even when instruments seem to make sense but especially if one fails. Do not just cross check the failed instrument as there may be cascaded problems and the initial diagnosis may be incorrect.
Original NASA ASRS Text
Title: TBM7 pilot reported an altitude deviation resulted from a pitot static system anomaly.
Narrative: On climb out in hard IMC/turbulence/rain I had a complete airspeed indicator failure on pilot side. I misdiagnosed this as a pitot failure (since glass instruments were still reporting altitude and the indication 'seemed to make sense' for stage of climb out) and began to operate off copilot airspeed but otherwise pilot side instruments for altitude and heading. Autopilot kicked off when airspeed on G600 failed. Unfortunately it was still reporting altitude and I believed what I saw. I leveled on heading 270 at indicated 5;000 feet and began to diagnose/debug. Checked pitot heat; checked power settings; etc. while hand-flying to maintain altitude [and] heading. High workload environment to say the least. After several other steps; I pulled the alternate static - immediately restored airspeed indicator on pilot side but; to my surprise; altitude also immediately wound up to approximately 7;500-8;000 feet. Apparently it was not a pitot tube problem but a static problem. I cross checked to GPS altitude and began correcting; while hand-flying and maintaining 270. ATC no doubt saw same as me - a near instantaneous altitude gain of 2;500-3;000 feet - and contacted me for an immediate course change to 360. I complied and we worked together to get back to assigned altitude.Learnings: Cross check constantly in IMC even when instruments seem to make sense but especially if one fails. Do not just cross check the failed instrument as there may be cascaded problems and the initial diagnosis may be incorrect.
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.