Air carrier captain reported concerns regarding de-icing procedures.

Attributes
ACN	1700924
Time
Date	201911
Place
Locale Reference	ORD.Airport
State Reference	IL
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 168 Flight Crew Type 1383
Events
Anomaly	Deviation - Procedural Published Material / Policy Ground Event / Encounter Other / Unknown

Narrative:

When we were in the new deice pad at ord; we watched an [aircraft] in front of us get deiced. The deice crew used type 1 on the wings then type 4 on the wings. They then moved to the fuselage and sprayed type 1 again. Finally; the tail and sprayed type 1 then type 4. I have 2 concerns. Does the overspray of type 1 onto the already sprayed type 4 contaminate or dilute the type 4? Is the time they give for the beginning of the second application accurate?

Original NASA ASRS Text

Title: Air carrier Captain reported concerns regarding de-icing procedures.

Narrative: When we were in the new deice pad at ORD; we watched an [aircraft] in front of us get deiced. The deice crew used Type 1 on the wings then Type 4 on the wings. They then moved to the fuselage and sprayed Type 1 again. Finally; the tail and sprayed Type 1 then Type 4. I have 2 concerns. Does the overspray of Type 1 onto the already sprayed Type 4 contaminate or dilute the Type 4? Is the time they give for the beginning of the second application accurate?

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.