What happened
On May 21, 2010, a Cessna 152, registration CS-ASQ, operated by Gestair Flying Academy, was conducting a solo instructional flight at Cascais Municipal Aerodrome. During the taxi phase, the student pilot experienced significant difficulty understanding radio instructions provided in English by Ground Control (SMC).
After receiving taxi instructions, the pilot struggled to perform correct readbacks, at one point citing radio equipment issues to explain the communication breakdown. Despite receiving explicit instructions to hold short of the runway, the pilot entered the active runway and taxied toward the takeoff position. This unauthorized movement created a conflict with an aircraft on final approach, forcing that aircraft to execute a go-around to avoid a collision.
The investigation
The GPIAAF investigation focused on the breakdown in communication between the student pilot and Air Traffic Services. The investigation established that the student pilot, while having passed theoretical examinations, lacked the necessary English proficiency to handle real-time, rapid-fire instructions.
Investigators examined the radio logs and found that the Ground Controller spoke at a very high rate of speech, which exacerbated the pilot's inability to process the information. While the pilot was able to repeat standard phrases from manuals, they failed to comprehend the specific restrictive content of the instructions. The investigation also noted that the Tower Controller (TWR) eventually switched to Portuguese to alert the pilot to the severity of the runway incursion, demonstrating a more effective approach to managing the student's difficulties.
Findings
- The student pilot entered the runway without authorization because they failed to correctly interpret the instruction to hold short.
- The pilot's English proficiency was insufficient for the complexities of live aeronautical communications.
- The Ground Controller's rapid rate of speech contributed to the pilot's inability to assimilate instructions.
- The pilot's readbacks were often technically correct in terms of using standard phrases, but they did not reflect an actual understanding of the instructions' meaning.
Safety action
To prevent future occurrences, the following recommendations were made:
- To Gestair Flying Academy: Review the flight training program to ensure student pilots are fully capable of performing mandatory radio communications before conducting solo flights, and establish procedures to clarify when communications should switch between English and Portuguese to ensure safety.
- To NAV Portugal, E.P.E.: Recommend that controllers, particularly at aerodromes with high student pilot density, use clear and deliberate speech to assist pilots experiencing communication difficulties.