Boeing 757-258, G-STRZ
Date of occurrence: 28 January 2009
Summary:
The aircraft had a blocked pitot tube, causing an airspeed discrepancy, which was detected early during the takeoff roll. The commander decided to continue the takeoff and deal with the problem whilst airborne. After passing FL180 the crew selected the left Air Data switch to ALTN, believing this isolated the left Air Data Computer (ADC) from the Autopilot & Flight Director System (AFDS). Passing FL316, the VNAV mode became active and the Flight Management Computer’s (FMCs), which use the left ADC as their input of aircraft speed, sensed an overspeed condition and provided a pitch-up command to slow the aircraft. The co-pilot was concerned about the aircraft’s behaviour and, after several verbal prompts to the commander, pushed the control column forward. The commander, uncertain as to what was failing, believed that a stick-pusher had activated. He disengaged the automatics and lowered the aircraft’s nose, then handed over control to the co-pilot. A “MAYDAY” was declared and the aircraft returned to Accra. The operator’s subsequent engineering investigation discovered the remains of a beetle-like creature in the left pitot system.
The aircraft had a blocked pitot tube, causing an airspeed discrepancy, which was detected early during the takeoff roll. The commander decided to continue the takeoff and deal with the problem whilst airborne. After passing FL180 the crew selected the left Air Data switch to ALTN, believing this isolated the left Air Data Computer (ADC) from the Autopilot & Flight Director System (AFDS). Passing FL316, the VNAV mode became active and the Flight Management Computer’s (FMCs), which use the left ADC as their input of aircraft speed, sensed an overspeed condition and provided a pitch-up command to slow the aircraft. The co-pilot was concerned about the aircraft’s behaviour and, after several verbal prompts to the commander, pushed the control column forward. The commander, uncertain as to what was failing, believed that a stick-pusher had activated. He disengaged the automatics and lowered the aircraft’s nose, then handed over control to the co-pilot. A “MAYDAY” was declared and the aircraft returned to Accra. The operator’s subsequent engineering investigation discovered the remains of a beetle-like creature in the left pitot system.
Report name:
Boeing 757-258, G-STRZ
Boeing 757-258, G-STRZ
Registration:
G-STRZ
G-STRZ
Type:
Boeing 757-258
Boeing 757-258
Location:
Following departure from Accra, Ghana
Following departure from Accra, Ghana
Date of occurrence:
28 January 2009
28 January 2009
Category:
Commercial Air Transport - Fixed Wing
Commercial Air Transport - Fixed Wing
Summary:
The aircraft had a blocked pitot tube, causing an airspeed discrepancy, which was detected early during the takeoff roll. The commander decided to continue the takeoff and deal with the problem whilst airborne. After passing FL180 the crew selected the left Air Data switch to ALTN, believing this isolated the left Air Data Computer (ADC) from the Autopilot & Flight Director System (AFDS). Passing FL316, the VNAV mode became active and the Flight Management Computer’s (FMCs), which use the left ADC as their input of aircraft speed, sensed an overspeed condition and provided a pitch-up command to slow the aircraft. The co-pilot was concerned about the aircraft’s behaviour and, after several verbal prompts to the commander, pushed the control column forward. The commander, uncertain as to what was failing, believed that a stick-pusher had activated. He disengaged the automatics and lowered the aircraft’s nose, then handed over control to the co-pilot. A “MAYDAY” was declared and the aircraft returned to Accra. The operator’s subsequent engineering investigation discovered the remains of a beetle-like creature in the left pitot system.
The aircraft had a blocked pitot tube, causing an airspeed discrepancy, which was detected early during the takeoff roll. The commander decided to continue the takeoff and deal with the problem whilst airborne. After passing FL180 the crew selected the left Air Data switch to ALTN, believing this isolated the left Air Data Computer (ADC) from the Autopilot & Flight Director System (AFDS). Passing FL316, the VNAV mode became active and the Flight Management Computer’s (FMCs), which use the left ADC as their input of aircraft speed, sensed an overspeed condition and provided a pitch-up command to slow the aircraft. The co-pilot was concerned about the aircraft’s behaviour and, after several verbal prompts to the commander, pushed the control column forward. The commander, uncertain as to what was failing, believed that a stick-pusher had activated. He disengaged the automatics and lowered the aircraft’s nose, then handed over control to the co-pilot. A “MAYDAY” was declared and the aircraft returned to Accra. The operator’s subsequent engineering investigation discovered the remains of a beetle-like creature in the left pitot system.
