A C172 instructor reported narrowly missing phx class B airspace thanks to a warning from ffz tower.

Attributes
ACN	1190266
Time
Date	201407
Local Time Of Day	0601-1200
Place
Locale Reference	FFZ.Airport
State Reference	AZ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Flight Phase	Cruise
Flight Plan	None
Person 1
Function	Instructor
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 10 Flight Crew Total 10000 Flight Crew Type 3000
Events
Anomaly	No Specific Anomaly Occurred All Types

Narrative:

Training flight from class D airport beneath class B (phx). Flew to A39 to practice takeoff and landings. As we were returning over chd at 2;700 ft MSL we ended up further west than we intended. We were also about 2;700 MSL when falcon tower told us that we were about ready to penetrate the floor of the phx class B. We did a quick right turn and descended to avoid class B airspace.

Original NASA ASRS Text

Title: A C172 instructor reported narrowly missing PHX Class B airspace thanks to a warning from FFZ Tower.

Narrative: Training flight from Class D airport beneath Class B (PHX). Flew to A39 to practice takeoff and landings. As we were returning over CHD at 2;700 FT MSL we ended up further west than we intended. We were also about 2;700 MSL when Falcon Tower told us that we were about ready to penetrate the floor of the PHX Class B. We did a quick right turn and descended to avoid Class B airspace.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.