MD11 captain reports inadvertently turning of IRU #1 while attempting to adjust the speaker volume o...

Attributes
ACN	986495
Time
Date	201112
Local Time Of Day	0601-1200
Place
Locale Reference	ZKC.ARTCC
State Reference	KS
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	MD-11
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	INS / IRS / IRU
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Engineer
Experience	Flight Crew Last 90 Days 75 Flight Crew Total 13700 Flight Crew Type 1381
Events
Anomaly	Deviation - Procedural Published Material / Policy

Narrative:

In cruise at FL370; I was pilot flying and had turned the volume control up on my speaker not realizing I had turned it almost all the way. ATC made a transmission to another aircraft and as it was very loud; I quickly reached up to turn the volume down and realized as I did so that I had inadvertently selected the #1 IRU off. I passed control of the aircraft to my first officer; got out the QRH (quick reference handbook) and complied with the abnormal alert 'IRU _ fail' checklist. At no time did the aircraft deviate in any axis; nor was there any course deviation. The rest of the flight was normal. This has happened before to other crews on this aircraft. I was aware of the problem of the speaker volume control knob being adjacent to the IRU control panel. The knobs are shaped differently; something I was well aware of. This was a self-induced problem. Maintenance was notified at the arrival gate and reset the IRU to the gate position for the next outbound flight. It may help to have the IRU knobs designed to be pulled before selecting off ... That or a guard of some sort over the IRU knobs. Bottom line ... Lesson learned ... No matter how familiar with the aircraft; look before one moves a switch or knob!

Original NASA ASRS Text

Title: MD11 Captain reports inadvertently turning of IRU #1 while attempting to adjust the speaker volume on the overhead panel. Flight continues to destination.

Narrative: In cruise at FL370; I was pilot flying and had turned the volume control up on my speaker not realizing I had turned it almost all the way. ATC made a transmission to another aircraft and as it was very loud; I quickly reached up to turn the volume down and realized as I did so that I had inadvertently selected the #1 IRU off. I passed control of the aircraft to my First Officer; got out the QRH (Quick Reference Handbook) and complied with the Abnormal Alert 'IRU _ Fail' checklist. At no time did the aircraft deviate in any axis; nor was there any course deviation. The rest of the flight was normal. This has happened before to other crews on this aircraft. I was aware of the problem of the speaker volume control knob being adjacent to the IRU control panel. The knobs are shaped differently; something I was well aware of. This was a self-induced problem. Maintenance was notified at the arrival gate and reset the IRU to the gate position for the next outbound flight. It may help to have the IRU knobs designed to be pulled before selecting OFF ... that or a guard of some sort over the IRU knobs. Bottom line ... lesson learned ... no matter how familiar with the aircraft; look before one moves a switch or knob!

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.

MD11 captain reports inadvertently turning of IRU #1 while attempting to adjust the speaker volume on the overhead panel. Flight continues to destination.