Air carrier flight crew reported they exceeded an altitude restriction while on the KATMN5 SID.

Attributes
ACN	1416882
Time
Date	201701
Local Time Of Day	1801-2400
Place
Locale Reference	PHX.Airport
State Reference	AZ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Large Transport
Operating Under FAR Part	Part 121
Flight Phase	Climb
Route In Use	SID KATMN5
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 146 Flight Crew Type 146
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 150
Events
Anomaly	Conflict Airborne Conflict Deviation - Altitude Overshoot Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance

Narrative:

Our clearance out of phx was to depart on the KATMN5 departure; climb via the SID. The KATMN5 has a top altitude of 8000 feet and a crossing restriction at vanzz intersection of at or below 8000 feet. Both were briefed and 8000 feet was set in the altitude window. After takeoff we were handed off to phx departure. As we began to turn left towards davzz intersection; phx departure gave us the revised clearance to 'climb via the SID; except maintain FL210.' we read back the clearance; I asked for VNAV on the automation; then we put FL210 in the altitude box; and I engaged the autopilot.at this point we had a miscommunication about the clearance and I thought phx departure wanted us to 'climb and maintain' FL210. Both the captain and I questioned each other about the clearance; and then removed the restriction of at or below 8000 feet at vanzz because of a misunderstanding of the climb clearance. We were then given (by phx departure) that we had traffic around 2 o'clock. Traffic was in sight and we were climbing around 3000-3500 FPM because we were light. We then received an RA with the traffic; which we complied with; and maintained visual separation. Shortly afterwards; phx departure told us that we needed to maintain 8000 feet at vanzz. We explained that we believed he had given us a clearance to 'climb and maintain' FL210 which removes all restrictions. At that point we realized that we had made a mistake and misinterpreted the 'climb via' clearance.

Original NASA ASRS Text

Title: Air carrier flight crew reported they exceeded an altitude restriction while on the KATMN5 SID.

Narrative: Our Clearance out of PHX was to depart on the KATMN5 Departure; climb via the SID. The KATMN5 has a top altitude of 8000 feet and a crossing restriction at VANZZ intersection of at or below 8000 feet. Both were briefed and 8000 feet was set in the altitude window. After takeoff we were handed off to PHX Departure. As we began to turn left towards DAVZZ intersection; PHX Departure gave us the revised clearance to 'climb via the SID; except maintain FL210.' We read back the clearance; I asked for VNAV on the automation; then we put FL210 in the altitude box; and I engaged the autopilot.At this point we had a miscommunication about the clearance and I thought PHX Departure wanted us to 'climb and maintain' FL210. Both the Captain and I questioned each other about the clearance; and then removed the restriction of at or below 8000 feet at VANZZ because of a misunderstanding of the climb clearance. We were then given (by PHX Departure) that we had traffic around 2 o'clock. Traffic was in sight and we were climbing around 3000-3500 FPM because we were light. We then received an RA with the traffic; which we complied with; and maintained visual separation. Shortly afterwards; PHX Departure told us that we needed to maintain 8000 feet at VANZZ. We explained that we believed he had given us a clearance to 'climb and maintain' FL210 which removes all restrictions. At that point we realized that we had made a mistake and misinterpreted the 'climb via' clearance.

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.