Boeing 737-800 Qrh Quick Reference Handbook [extra Quality] -

: This chapter covers issues that do not trigger a specific warning light, such as fuel leaks or ditching.

: These checklists often include memory items (demarcated by a dashed line in the manual) to isolate the affected engine quickly. boeing 737-800 qrh quick reference handbook

: This requires immediate action, including donning oxygen masks and initiating an emergency descent to 10,000 feet or the lowest safe altitude. : This chapter covers issues that do not

The QRH is a stand-alone document that summarizes essential procedures for various in-flight scenarios. It is strictly used once the aircraft is "in flight"—defined as the moment the parking brake is released to commence flight. boeing 737-800 qrh quick reference handbook