Arabic to English Tech/Engineering Military / Defense artillery

These are the safety instructions for an artillery system integrated into a vehicle.

This word occurs twice:
1. For safety reasons, the crew are advised to keep out of an area defined as في سطحة القذيفة
2. As part of maintenance, the crew must check قفل سطحة مناولة القذائف

I have doubts about whether it refers to the same concept. Do you think that the first case means a geometric 'plane', especially as used with في ?

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