Communications between pilots and controllers is essentialto the successful operation of the ATC system. Communications between controllers is also essential. A standard phraseology has been developed to avoid ambiguity in communications. However, the standards are sometimes violated by using other jargon and than may have consequences.

Discuss the importance of clear unambiguouscommunications between pilots and controllers and between controllers in the safe and expeditious operation of the air traffic control system. In your initial post, cite some examples of the consequences of ambiguity in communications either from your own experience or research some of the accidents and incidents from NTSB or ASRS where ambiguity in communications became a safety hazard.

In your response to your classmates, cite either supporting examples if you agree or counter examples if you disagree with their post.

Here is an example from my experience:

Philadelphia International tower was operating on a VFR day but with busy traffic. The ground controller had taxiedthree airliners that were departing to the arrival runway, where they were holding. To get to their departure runway they had to cross the arrival runway and that crossing required permission from the local controller. The ground controller, standing next to the local controller in the tower said to the local controller: "Cross three for 27R at Sierra". The local controller was very busy and responded sarcastically: "Yea right!", meaning don't bother me. However, the ground controller took that response as "Affirmative", and gave instructions for the three airliners to cross runway 27R. Unknown to the ground controller, and missed by the busy local controller, there was another airliner on final for landing on runway 27R, as the three airlines were crossing runway 27R at the Sierra intersection (which is fairly close to the touchdown zone for landing traffic on runway 27R). Fortunately the pilot of the landing aircraft saw the airliners on the runway and executed a go around, avoiding a tragic accident. The go around, of course, caused the local and ground controllers to realize their mistake. Most fortunately, the weather was clear VFR; however, had the weather been IMC and near minimums, the landing aircraft pilot would probably not have been able to see the crossing traffic until it was too late to go around and there would have been a tragic accident at PhiladelphiaInternational.