Date: 201412
Local time of day: 1201-1800
Location: TUS.Airport, AZ
Light: Daylight
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
ATC / advisory: Tower TUS
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Communication Breakdown; Confusion; Distraction
Second reporter function: Supervisor / CIC
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Detector: Person Air Traffic Control
When detected: In-flight
Contributing factors: Procedure
Primary problem: Procedure

Narrative: It was early in the morning and we just had rain until approximately an hour earlier. Now the sun had just broken out of the clouds. I had asked the ground controller to drop the second row of shades. Which they replied 'They are already down'. It was unusually bright and glary due to the rain water reflecting off of the large open tarmac area on the southeast side of the terminal. I was handed three departures from ground control. All three were westbound. Two Aircraft X type followed by a cargo. I thought I would coordinate a left turn for the first aircraft to help out approach control. I saw that a sweeper was abeam Alpha 17 and told him to exit 11L. It's fairly common for him to not respond until he is actually clear of the runway. My main error was thinking he was doing this; that he was waiting to respond until he was actually clear of the runway; so this did not strike me as unusual. I scanned the runway and did not see the sweeper on the runway. I cleared Aircraft X for takeoff. I watched Aircraft X as he began his departure roll. Then I saw some movement at the departure end of the runway. I immediately grabbed the binoculars to get a better view. I saw that it was the Sweeper. At this point Aircraft X was near Alpha 11; and I got on the radio and told the sweeper to exit the runway twice with no response. As Aircraft X rotated at Alpha 13 the vehicle was clearing at Alpha 17; I then quickly tried to reach out to him twice but he had cleared the runway by the second transmission.Height and location of the tower. Due to the low height of the tower cab and the distance to Alpha 13; it's hard to see vehicles without weather. Today it was made worse by having a majority of overcast yet a large amount of brightness and glare from the water on the ground. I think the new tower that is being built will hopefully alleviate this issue as we've had many errors at that end of the runway in the last 10 years or so. Communication Vehicles are issued to clear the runway; and very often the vehicles don't respond until they are actually clear the runway. They don't report 'Roger' or 'Exiting' 'Wilco' etc.Sometimes they will clear the runway and will not report off (which isn't a requirement.) due to this controllers have gotten in the habit of clearing people for takeoff without a response from the vehicle and just observing that they are clear of the runway. I think as a facility the vehicles should acknowledge the receipt of a transmission at all times. Radio Dead spot we have reported many times about a dead spot at Runway 21 near Delta and at Runway 29R at Alpha 17. To my knowledge that has never been fixed. I'm not sure if that was a factor this time or not; but it has been a factor before with aircraft holding in position and not responding to the tower. Which was the same location as where the sweeper was when the incident occurred.


Second narrative: A Sweeper was on RWY 11L sweeping near the departure end of the rwy near taxiway A17. The Local Controller instructed the sweeper to exit the runway. A minute later the controller cleared Aircraft X for takeoff. The controller then coordinated a heading for Aircraft X with the TRACON; issued the instruction to Aircraft X; at this point Aircraft X was starting their take-off roll. As the controller was scanning the runway he spotted the vehicle near the end of the runway; because of the poor view of that end of the runway it is very difficult to see clearly; as he realized the vehicle had not exited the runway; he instructed the sweeper to exit immediately; once again he received no reply. As he attempted to reach out to the sweeper he realized that Aircraft X was safer continuing its take-off roll than attempting to abort. Aircraft X became airborne at approximately A13 as the sweeper exited at A17.As the Front Line Manager (FLM) I was at the FLM desk working administrative duties as well as observing the operation. I believe the actions leading up to this event included drift on all our parts; as we become so accustomed to the sweeper getting on and off the rwy. In this instance the time between when the controller instructed the sweeper to exit the runway and Aircraft X starting his take-off roll allowed the controller to assume the vehicle had exited the runway. In researching the incident it was learned that the vehicle claimed to not have heard any of the instructions and was unaware of what was occurring; he happened to be in an older sweeper with older radios. So in addition to the issues with the poor tower visibility; the safety drift; the equipment on the vehicle appears to have contributed to this event as well. The building of the new air traffic control tower will help in providing better views of the airport. This event has provided a good wakeup call for myself as the FLM to make certain that I provide the support the controllers need in different situations. Also a discussion with the sweeper unit reviewing the importance of their vehicle support staff receiving periodic updates on scanning and helping out if needed; at a minimum to make certain they are also scanning and being an active partner with the controllers.


Synopsis: Two controllers and a pilot report of runway incursion due to a sweeper not exiting the runway and the Local Controller issuing a takeoff clearance.