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An MD80 pilot suggests that the stabilizer trim aural warning be much louder when the aircraft is in cruise with autoplt engaged.
| Attributes | |
| ACN | 699165 |
| Time | |
| Date | 200606 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Aircraft 1 | |
| Controlling Facilities | tower : saez.tower |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Series (DC-9-80) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| ASRS Report | 699165 |
| Events | |
| Anomaly | aircraft equipment problem : less severe |
| Independent Detector | other flight crewa |
| Resolutory Action | none taken : unable none taken : anomaly accepted |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
I'm a fairly recent MD80 pilot; having been displaced from my previous aircraft after 12 yrs. I still hear; and am annoyed by; the sound the trim system makes as it is moving in the MD80. However; I fly with many other pilots who after many; many yrs and thousands upon thousands of hours in the airplane simply do not notice that same sound. They've developed a complete immunity to the noise. Obviously; if one were to notice the sound of the trim system moving (as designed); while in level cruise flight; any impending bleed off in airspeed would be immediately recognized as such and corrected before it became an 'incident.' I suggest what to my mechanical and engineering untrained mind is a simple solution: namely; alter the wiring/software in the airplane; so that when altitude hold is engaged; there is some other warning bell; or horn; or 'stabilizer motion' voice warning that will alert in addition to the current buzzing sound. No doubt this alternation would require an investment of time and effort to satisfy whatever FAA requirements would have to be met; along with some financial costs. However; I'm completely confident that a repeat of an insidious loss of airspeed/approach to stall event could be prevented; a cost we could ill afford to incur.
Original NASA ASRS Text
Title: AN MD80 PLT SUGGESTS THAT THE STABILIZER TRIM AURAL WARNING BE MUCH LOUDER WHEN THE ACFT IS IN CRUISE WITH AUTOPLT ENGAGED.
Narrative: I'M A FAIRLY RECENT MD80 PLT; HAVING BEEN DISPLACED FROM MY PREVIOUS ACFT AFTER 12 YRS. I STILL HEAR; AND AM ANNOYED BY; THE SOUND THE TRIM SYS MAKES AS IT IS MOVING IN THE MD80. HOWEVER; I FLY WITH MANY OTHER PLTS WHO AFTER MANY; MANY YRS AND THOUSANDS UPON THOUSANDS OF HRS IN THE AIRPLANE SIMPLY DO NOT NOTICE THAT SAME SOUND. THEY'VE DEVELOPED A COMPLETE IMMUNITY TO THE NOISE. OBVIOUSLY; IF ONE WERE TO NOTICE THE SOUND OF THE TRIM SYS MOVING (AS DESIGNED); WHILE IN LEVEL CRUISE FLT; ANY IMPENDING BLEED OFF IN AIRSPD WOULD BE IMMEDIATELY RECOGNIZED AS SUCH AND CORRECTED BEFORE IT BECAME AN 'INCIDENT.' I SUGGEST WHAT TO MY MECHANICAL AND ENGINEERING UNTRAINED MIND IS A SIMPLE SOLUTION: NAMELY; ALTER THE WIRING/SOFTWARE IN THE AIRPLANE; SO THAT WHEN ALT HOLD IS ENGAGED; THERE IS SOME OTHER WARNING BELL; OR HORN; OR 'STABILIZER MOTION' VOICE WARNING THAT WILL ALERT IN ADDITION TO THE CURRENT BUZZING SOUND. NO DOUBT THIS ALTERNATION WOULD REQUIRE AN INVESTMENT OF TIME AND EFFORT TO SATISFY WHATEVER FAA REQUIREMENTS WOULD HAVE TO BE MET; ALONG WITH SOME FINANCIAL COSTS. HOWEVER; I'M COMPLETELY CONFIDENT THAT A REPEAT OF AN INSIDIOUS LOSS OF AIRSPD/APCH TO STALL EVENT COULD BE PREVENTED; A COST WE COULD ILL AFFORD TO INCUR.
Data retrieved from NASA's ASRS site as of January 2009 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.