The various embodiments herein disclose a method for monitoring non-invasive arterial oxygen saturation (SpO2), pulse rate (PR) and detecting level of carboxyhaemoglobin (COHb) in a blood flow of an aircraft pilot during an in-flight condition for detection of symptoms of hypoxia. The method comprises detection of an artery microcirculation of blood in forehead of the aircraft pilot by using an infrared (IR) photometric technique. A pulse oximetry (PO) reflectance sensor is installed over the detected artery with microcirculation in the forehead. The values of AI, VI and GI are combined with a signal strength and a signal quality of the PO sensor to calculate a final weighted index of confidence for SpO2 (CIsat) and PR (CIpr) measurements. The measured values of CIsat and CIpr are implemented to calculate an overall weighted confidence index (CI) to determines an accuracy of measurements of SpO2 and PR.
