PA-44 instructor pilot reported an near midair collision on final at dvt.

Attributes
ACN	1267057
Time
Date	201505
Local Time Of Day	0601-1200
Place
Locale Reference	DVT.Airport
State Reference	AZ
Environment
Light	Daylight
Aircraft 1
Make Model Name	PA-44 Seminole/Turbo Seminole
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Other RNAV Runway 7R
Person 1
Function	Pilot Not Flying Instructor
Qualification	Flight Crew Flight Instructor Flight Crew Commercial
Events
Anomaly	Conflict NMAC

Narrative:

While on final approach practicing RNAV 7R into dvt inside of I-17; without warning a BE300 accelerated underneath my aircraft. [The other aircraft] then sidestepped to 7L; where he had received landing clearance. Student pilot was practicing the RNAV 7R; with no deviation from centerline.tis is unreliable in the area of dvt.

Original NASA ASRS Text

Title: PA-44 instructor pilot reported an NMAC on final at DVT.

Narrative: While on final approach practicing RNAV 7R into DVT inside of I-17; without warning a BE300 accelerated underneath my aircraft. [The other aircraft] then sidestepped to 7L; where he had received landing clearance. Student pilot was practicing the RNAV 7R; with no deviation from centerline.TIS is unreliable in the area of DVT.

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.