Hold-Short Clearance and a Stepped-On Readback
You are taxiing a Cessna 172 at a towered Class D airport with two intersecting runways. Ground clears: “Cessna 12345, taxi to Runway 27 via Alpha, hold short Runway 17 at Alpha.” Your route along Alpha crosses Runway 17 before reaching Runway 27. Another pilot steps on the transmission, and you read back: “Taxi to Runway 27 via Alpha, cross Runway 17 at Alpha, Cessna 12345.” Ground does not reply. You are 200 feet from the hold-short line; the tower is sequencing several departures, and no aircraft is visible on Runway 17. Your passenger asks why you are stopping. Fuel is normal, visibility is 10 miles, and you are not time-critical. The hold-short markings are clear, but the readback you gave was not what Ground issued. You must decide what to do before reaching the line and how to resolve the communication safely without disrupting tower operations.
1. What is the safest immediate action as you approach the hold-short line, and why does the absence of visible traffic not change it?
Read the worked answer
Stop before the hold-short markings and do not cross Runway 17. The instruction was to hold short; your readback changed it to “cross,” which is a readback error, not an authorization. ATC’s silence after a stepped-on transmission is not a clearance. No visible traffic is not proof the runway is clear: an aircraft could be on short final, a departure could be rolling, or a vehicle could be on the runway. Crossing would create a runway incursion and possible collision. Keep the aircraft firmly on the Alpha side of the hold-short line, keep the passenger briefed, and use the time to correct the communications. Do not cross until you receive an explicit instruction from ATC.
2. Compose the transmission you would make to correct the readback, and explain what information you need back.
Read the worked answer
Make a concise correction on the ground frequency: “Ground, Cessna 12345, correction. I am holding short of Runway 17 at Alpha. My previous readback said cross Runway 17; I do not have a crossing clearance. Confirm hold short and taxi to Runway 27.” This identifies you, states your actual position, flags the erroneous readback, and asks for the governing instruction. Do not say only “correction” without stating the correct hold-short and position, because the controller may not know which part you are correcting. If the frequency is blocked, wait and try again; if still blocked, hold and contact tower on the tower frequency. You need an explicit hold-short or crossing instruction before moving.
3. What human-factor and operational defenses would you apply after this event?
Read the worked answer
Use a verbal readback that includes “hold short Runway 17 at Alpha” verbatim; never substitute “cross” or omit the hold-short instruction. If a transmission is stepped on, ask “say again” rather than assuming. Apply sterile cockpit during taxi, brief the route and hold-short points, and watch for expectation bias-wanting to reach Runway 27 can make “hold short” sound like “cross.” Treat ATC silence as no clearance. After the event, report the blocked transmission and readback error to ground so the controller can correct the record. Consider writing the taxi route and hold-short points on the kneeboard, and use a physical checkpoint at the hold-short line.