An MD11 captain turned off an IRU in flight when he intended to open the flight station door because...

Narrative:

After level off at initial cruise altitude; the relief flight officer entered the proper code to request entry to the flight deck. The captain reached up to disarm the fdas door lock; and inadvertently rotated the switch for the number 2 inertial reference unit (IRU) to the off position. We referred to the quick reference handbook (QRH); which directed the first officer to select use of the aux IRU for his flight and navigation inputs. We also consulted the QRH to ensure that we still had the requisite navigation equipment to continue our flight. The flight continued to destination with no incident. This is certainly not the first time that a pilot in the left seat has accidentally turned off an IRU while intending to release the lock on the fdas. While the switches of the two systems are somewhat different in shape; they are located within inches of each other on the overhead panel. This co-location of the switches; plus the lack of a guard over the IRU switches; poses an on-going risk of a repetition of this event. Suggestions for avoiding this event in the future could include: always look up at exactly where your hand is going before changing a switch position. Move location of either fdas or IRU switches so they are not co-located. Install switch guards over the IRU switches so that they cannot be inadvertently repositioned once the irus are initialized during preflight.

Original NASA ASRS Text

Title: An MD11 Captain turned off an IRU in flight when he intended to open the flight station door because the switches are located very close to each other on the overhead panel.

Narrative: After level off at initial cruise altitude; the Relief Flight Officer entered the proper code to request entry to the flight deck. The Captain reached up to disarm the FDAS door lock; and inadvertently rotated the switch for the number 2 inertial reference unit (IRU) to the off position. We referred to the Quick Reference Handbook (QRH); which directed the First Officer to select use of the aux IRU for his flight and navigation inputs. We also consulted the QRH to ensure that we still had the requisite navigation equipment to continue our flight. The flight continued to destination with no incident. This is certainly not the first time that a pilot in the left seat has accidentally turned off an IRU while intending to release the lock on the FDAS. While the switches of the two systems are somewhat different in shape; they are located within inches of each other on the overhead panel. This co-location of the switches; plus the lack of a guard over the IRU switches; poses an on-going risk of a repetition of this event. Suggestions for avoiding this event in the future could include: Always look up at exactly where your hand is going before changing a switch position. Move location of either FDAS or IRU switches so they are not co-located. Install switch guards over the IRU switches so that they cannot be inadvertently repositioned once the IRUs are initialized during preflight.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	999142
Time
Date	201203
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZZ.ARTCC
State Reference	FO
Environment
Flight Conditions	VMC
Light	Night
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	Pilot Flying First Officer
Qualification	Flight Crew Flight Engineer Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 110 Flight Crew Total 12000 Flight Crew Type 2000
Events
Anomaly	Aircraft Equipment Problem Less Severe

An MD11 captain turned off an IRU in flight when he intended to open the flight station door because the switches are located very close to each other on the overhead panel.