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A C525 pilot unintentionally disconnected the autopilot near the altitude capture point and did not hear the altitude alert or autopilot disconnect sounds. Reporter stated both alerts are at a high frequency and not loud enough for some older pilots to hear.
| Attributes | |
| ACN | 852058 |
| Time | |
| Date | 200909 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | Citationjet (C525/C526) - CJ I / II / III / IV |
| Operating Under FAR Part | Part 91 |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Altitude Alert |
| Person 1 | |
| Function | Pilot Flying Single Pilot |
| Experience | Flight Crew Last 90 Days 25 Flight Crew Total 20000 Flight Crew Type 300 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Altitude Overshoot |
Narrative:
Climb received to 36;000 ft. At 34;500 ft asked for 34;000 ft for final and given. During descent autopilot bumped out and alert missed. Controller called and advised I was low; returned to assigned altitude. Many older pilots have trouble hearing certain frequencies. The altitude and autopilot disconnect in the aircraft are high frequencies. I asked cessna to change the tone generator or turn up volume and was told that was the way it was certified and could not be changed. The autopilot light on the EFIS is so small anyone could miss it. There needs to be a voice like for 'terrain' that announces autopilot disconnected or just plain autopilot. There are 4 or 5 tones in the aircraft and many; if you can hear them; sound the same.
Original NASA ASRS Text
Title: A C525 pilot unintentionally disconnected the autopilot near the altitude capture point and did not hear the altitude alert or autopilot disconnect sounds. Reporter stated both alerts are at a high frequency and not loud enough for some older pilots to hear.
Narrative: Climb received to 36;000 FT. At 34;500 FT asked for 34;000 FT for final and given. During descent autopilot bumped out and alert missed. Controller called and advised I was low; returned to assigned altitude. Many older pilots have trouble hearing certain frequencies. The altitude and autopilot disconnect in the aircraft are high frequencies. I asked Cessna to change the tone generator or turn up volume and was told that was the way it was certified and could not be changed. The autopilot light on the EFIS is so small anyone could miss it. There needs to be a voice like for 'terrain' that announces autopilot disconnected or just plain autopilot. There are 4 or 5 tones in the aircraft and many; if you can hear them; sound the same.
Data retrieved from NASA's ASRS site as of April 2012 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.