Technicians reported aircraft settled on nose landing gear door during a strut height check.

Attributes
ACN	1754529
Time
Date	202008
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Parked
Flight Plan	IFR
Component
Aircraft Component	Nose Gear Door
Person 1
Function	Technician
Qualification	Maintenance Airframe Maintenance Powerplant
Person 2
Function	Technician
Qualification	Maintenance Powerplant Maintenance Airframe
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy Ground Event / Encounter Object

Narrative:

Aircraft X required a weight on wheels 'H' check of the nlg (nose landing gear) and right medium large transport (main landing gear). We centered the ladder in between the nlg doors and I began to install the pressure gauge to the top fitting on the nlg strut. While doing so the ladder must have shifted positions. During this time I never heard any loud hissing to indicate to me that air was being released due to extreme noise from our a/C and other a/C & vehicles in the vicinity. My partner went up to turn off the a/C power due to the noise level. A few minutes after coming down from the ladder I noticed the left nlg door sitting on top of the ladder. I immediately moved the ladder to prevent any further damage. I suspect that air escaped from the t-handle on top of the tooling and due to the noise I wasn't able to hear it. The very slow release of air may have caused us to not notice the plane had shifted.

Original NASA ASRS Text

Title: Technicians reported aircraft settled on Nose Landing Gear Door during a Strut Height Check.

Narrative: Aircraft X required a weight on wheels 'H' check of the NLG (Nose Landing Gear) and right MLG (Main Landing Gear). We centered the ladder in between the NLG doors and I began to install the pressure gauge to the top fitting on the NLG strut. While doing so the ladder must have shifted positions. During this time I never heard any loud hissing to indicate to me that air was being released due to extreme noise from our A/C and other A/C & vehicles in the vicinity. My partner went up to turn off the A/C power due to the noise level. A few minutes after coming down from the ladder I noticed the left NLG door sitting on top of the ladder. I immediately moved the ladder to prevent any further damage. I suspect that air escaped from the t-handle on top of the tooling and due to the noise I wasn't able to hear it. The very slow release of air may have caused us to not notice the plane had shifted.

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.