וגם שצוות יכול לכלול גם גורמים שאינם נמצאים בתא הטייסים ובכלל לא במטוס. 

לסוכנות החלל של ארה"ב NASA יש מעורבות עמוקה בכל תחומי בטיחות הטיסה, לא רק חלל. היא מפעילה מערכת דיווח אירועי בטיחות טיסה ASRS. הסוכנות מוציאה ירחון אינטרנטי בשם Callback. בירחון של חודש דצמבר התפרסם סיפור אירוע לא שגרתי והדרך שהצוות "תפעל" אותו. אפשר ללמוד מזה לא מעט, על תושייה, עבודת צוות, שיתוף פעולה ומחשבה מחוץ לקופסה. באופן כללי, יש כיום מגמה, בעולם בטיחות הטיסה, לנסות ללמוד ממקרים שנוהלו בצורה מוצלחת ולא להסתמך רק על חקירות של תקריות, תאונות ומצבים בהם צוותים תפקדו לא הכי טוב. 

להלן הסיפור:

■ My First Officer and I…taxied out to Runway XXL. On the takeoff roll, as soon as the main wheels got airborne…we heard an incredibly loud squeal over the radios and intercom. It was the same loud squeal we hear when the Ramp plugs in a faulty headset. It was so loud, we were unable to hear ATC, communicate with each other over the intercom, or communicate with the flight attendants. We immediately used hand signals to communicate, raising the landing gear and flaps in accordance with the AOM. As soon as we were clean and safely away from the ground, the First Officer turned right to 360, continued the climb to 4,000 feet, engaged the autopilot, and we began troubleshooting. We tried unplugging each individual headset as well as unplugging both headsets and selecting the overhead speaker. We also tried selecting COMM 2. No matter what we did, the continuous loud squeal remained. So, we unplugged our headsets and began making all radio transmissions in the blind utilizing the hand-held microphone. We squawked XXXX and proceeded on our cleared route…and began our climb to FL280. We sent Dispatch a message and had her coordinate with ATC to make sure we were cleared to FL280. Dispatch also relayed our clearance to descend [and] cross ZZZZZ1 at 9,000 feet, as well as our clearance to descend to 4,000 feet and shoot the [approach for] Runway XYL. Dispatch also contacted ZZZ1 Tower and relayed our clearance to land.

Because I was unable to verbally communicate with ATC or the flight attendants, I determined this could develop into a safety of flight incident, so I began looking for ways to lower this risk. Because the QRH does not address this scenario, in accordance with the AOM, I told the FO I’d like to pull the Circuit Breaker (CB) to COMM 1 and then COMM 2 to see if we could get rid of the squeal. She agreed it was worth a try. In accordance with the AOM, I first pulled the CB to COMM 1. We plugged our headsets back in, but the squeal remained. So, I reset the CB to COMM 1 and then pulled the CB to COMM 2, but the squeal remained. At cruise, the flight attendants called us. Since I was unable to communicate with them, I got up out of my seat, looked through the peephole, and opened the door. I told them what was going on, asked them to secure the cabin, and give me two chimes when they were seated. They complied with this and later gave me two chimes to let me know they were seated. The FO and I briefed the [arrival] to XYL, then completed the Descent and Approach Checklist. After landing on XYL, we cleared the runway and came to a stop. I called Tower on my cell phone and received our clearance to taxi to the gate.

After pulling into the gate, I made two logbook write-ups, contacted Dispatch, talked to the Chief Pilot on Call, the Company, and the local ZZZ1 Chief Pilot.