Chapter sixteen covered the emergency return, where a crew declares distress and the field is held for it. This chapter covers three events that put nobody in distress and are still the tower's to handle: a transmitter stuck open, a laser pointed at a crew on the final, and a passenger the cabin crew has had to restrain. None of them closes a runway. Each takes one specific action from the tower, and the traffic keeps moving while it is taken. The examples are at Bayview on runway two five right, wind two five zero at eight.
A stuck microphone
A radio transmits for as long as its push-to-talk switch is held down. A switch that sticks, a headset cord caught under a seat rail or a pilot's knee against the switch on the yoke keeps the transmitter keyed, and a keyed transmitter puts a carrier on the frequency. Everybody else hears it as a steady tone or a heterodyne squeal, and nobody hears anything else.
While the carrier is on the frequency, every instruction you transmit goes unheard: the landing clearance, the Line up and waitRunway two five right, line up and wait.Taxi onto the runway and stop on the centerline, staged for an imminent departure. It is not a takeoff clearance, and pilots treat the difference as absolute.Open in the glossary, the crossing for a vehicle. The aeroplane cannot tell you so, because its own transmitter is blocked by the same carrier. Nothing transmitted during the block can be assumed received.
The crew with the stuck switch usually does not know: the squeal filling every other headset is not audible in the aeroplane producing it. The tower reaches the crews through their second radio. Airline aeroplanes monitor the emergency frequency, one two one point five, on a second receiver, and controllers call it guard. A call on guard reaches every crew whose main radio is blocked:
Attention all aircraft, stuck microphone on tower frequency, check your microphones.
The call names the problem and asks every crew to check, because the tower rarely knows which aeroplane it is. The crew with the problem finds the switch and frees it, the carrier stops, and an apology on the tower frequency usually follows.
Bayview Tower, Southwest three one eight, sorry about that, stuck microphone, ten mile final runway two five right.
Southwest three one eight, Bayview Tower, roger, runway two five right, cleared to land.
Runway two five right, cleared to land, Southwest three one eight.
When the frequency clears, go back over what each aircraft was last told. An arrival Cleared to landRunway two five right, cleared to land.The runway is yours to land on. It may be issued while the aircraft ahead is still clearing, on the judgement that the runway will be free at the threshold.Open in the glossary before the block still has its clearance. An arrival that checked in during the block was never answered. A departure told to line up and wait during the block may have heard the instruction and may not have, and the safe assumption is that it did not. Say each of those again, in the order the traffic needs them, before anything new is issued. The departure at the Holding pointThe marked position at the runway entrance where a departure waits for its clearance. Crossing the marking without one is a runway incursion.Open in the glossary is usually first, because it has waited longest and the arrival behind it has been closing the whole time.
A laser on the final
A handheld laser pointed at an aeroplane on the final puts a bright flash through the windscreen. It does no damage to the aeroplane. It can leave the pilot who was looking that way with flash blindness for several minutes, at the point in the approach where the eyes are doing most of the work. The pilot who was not hit takes control, and the crew reports the event with the colour, the direction it came from, the position on the final and the altitude.
Bayview Tower, United one one nine zero, we've been hit by a laser, green, from the left, seven mile final, two thousand four hundred feet.
United one one nine zero, roger, laser.
The acknowledgement tells the crew the report was received. A crew with one pilot's eyesight gone for a minute does not want a conversation; it may ask for a go-around or carry on to the landing, and either is its choice. The rest of the tower's response is set out in the manual, and the first part of it is owed to every other aircraft near the field:
When a laser event is reported to an air traffic facility, broadcast on all appropriate frequencies a general caution warning every five minutes for 20 minutes following the last report.
PhraseologyUNAUTHORIZED LASER ILLUMINATION EVENT, (location), (altitude).
The broadcast gives the next crews on the same final the position and the altitude where the laser was, so they know where to expect it. At Bayview it goes out as soon as the first report has been acknowledged:
Attention all aircraft, unauthorized laser illumination event, seven mile final runway two five right, two thousand four hundred feet.
The manual asks for the caution to be repeated every five minutes for twenty minutes after the last report, and for the event to go on the recording for an hour with the time, place, altitude, colour and direction the pilot gave. The same paragraph tells the tower what to expect from the crews that hear the caution:
noteAll personnel can expect aircrews to regard lasers as an inflight emergency and may take evasive action to avoid laser illumination. Additionally, other aircraft may request clearance to avoid the area.
A crew that asks for a different runway, or for a turn away from the reported spot, gets it when the traffic allows. The facility reports the event onward to the FAA and the local police after the fact. The tower's part on the frequency is the acknowledgement, the caution, and the colour, direction, position and altitude written down while the crew is still saying them.
A passenger the crew has restrained
Cabin crews manage difficult passengers on most days without the flight deck hearing about it. Sometimes a passenger strikes a crew member or tries to open a door and has to be restrained. The captain lands with the passenger held, and the request that reaches the tower is for help on the ground.
Bayview Tower, Delta one four zero seven, we have a disruptive passenger restrained in the cabin, request police meet the aircraft on arrival.
Delta one four zero seven, roger, police will meet the aircraft.
Police will meet the aircraft, thank you, Delta one four zero seven.
Unless the crew declares an emergency, the aeroplane is flying normally, the approach is a normal approach, and the landing clearance comes in its turn. If the crew asks for priority, it gets it, and the tower does not ask the captain to justify the request. Most crews do not ask. What they want is a police car waiting when the doors open and a parking position where the passenger can be taken off without walking through a terminal.
The tower arranges both. A call goes to the airport police, and a word goes to the ground controller or the ramp that the aeroplane is going to a remote stand. The reply to the crew is short, so that it can be given once and relied on: police will meet the aircraft.
After the landing the aeroplane taxis to the stand and the police drive out to it. Their car is a vehicle on the movement area, with the same obligations as the rescue trucks in chapter sixteen and the ploughs in chapter eighteen. It calls the tower before any runway on its way and crosses when it is cleared to:
Bayview Tower, Police one, at the station, request cross runway three three to the remote stands.
Police one, cross runway three three.
Cross runway three three, Police one.
The car waits beside the stand until the aeroplane has parked and shut down, then pulls up behind it. The officers board, the passenger is taken off, and the car leaves.
Keeping the runway working
None of the three stops the traffic, and the tower's job while they are being handled is to keep it moving. The stuck microphone costs the most time, and the first call once it clears is to the departure that waited through it.
When the departure controller has asked for an initial heading, that heading goes at the front of the takeoff clearance: the heading, then the runway, then Cleared for takeoffRunway two five right, wind two five zero at eight, cleared for takeoff.The runway is yours to fly from. Runway number first, then the wind, then the clearance, always in that order.Open in the glossary. The crew hears the heading before the words that start the roll.
Alaska two seven, fly runway heading, runway two five right, cleared for takeoff.
Runway heading, runway two five right, cleared for takeoff, Alaska two seven.
The laser caution goes out between other transmissions and is repeated when a new report comes in; it does not hold up a clearance. The police car's crossings fit into the gaps the way any vehicle's do.
In the Sim
In ATC Simulator these three incidents happen in the tower seat, on the same ready-room setting as the bird strike in chapter sixteen, called Unusual occurrences, which runs from never through rare and normal to frequent, and they work offline. A departure's takeoff can bring only the stuck microphone. An arrival checking in on the final can bring any of the three, with one limit: a freighter, a military jet and a light single never carry a disruptive passenger. One story runs at a time. Lesson 23, Incidents on the frequency, walks through all three at Bayview on runway two five right with the wind two five zero at eight: a stuck microphone on Southwest three one eight on a ten mile final, Alaska two seven's runway heading takeoff once the frequency clears, a green laser reported by United one one nine zero at seven miles and two thousand four hundred feet, and Delta one four zero seven's disruptive passenger.
The stuck microphone keys open three to eight seconds after the movement and stays open for fifty to a hundred seconds. You hear the open carrier with a heterodyne whine, and every transmission on the tower frequency in that time is blocked and logged as not heard: clearances, vehicle calls and the laser caution alike. The guard call frees it four seconds later and earns points. While the switch is stuck, and for twenty seconds after it frees, nothing is charged to you: a loss of separation or a Runway incursionAnything on protected runway surface that should not be there: an aircraft past its hold line, a vehicle without approval. The accident category towers exist to prevent.Open in the glossary in that window is reported but not scored and does not count as a strike, a go-around costs nothing, and the ground queue's waiting time is forgiven.
The laser report comes five to fifteen seconds after an arrival checks in, green most of the time and sometimes blue, and sometimes with a pilot who has flash blindness. Saying RogerRoger.I received your whole transmission. It does not mean yes, and it is not a readback.Open in the glossary, laser within thirty seconds earns points; the caution broadcast within two minutes earns more; never broadcasting it costs points. The five-minute repeats and the remark on the recording are not modelled.
The disruptive passenger call comes six to fifteen seconds after the check-in. Telling the crew that police will meet the aircraft before the touchdown earns points. Left unsaid, the airline calls the police itself at the touchdown and you get no credit. The aeroplane parks on a remote stand, and a police car, Police one, drives out from the station, asks you for every runway on its way, waits beside the stand, pulls up behind the parked aeroplane and stays about two and a half minutes.
The sim understands the phrases this chapter teaches, including roger the laser and roger, police will meet you as alternatives, and the crossing clearance for Police one.