A CRJ700 dispatcher reported that a MEL making the GPWS inoperative also made the windshear warning ...

Narrative:

A far 121 dispatch release was cued for dispatch on aircraft. After reviewing the MEL for that aircraft; I found there is conflicting information regarding the GPWS windshear function (as the entire GPWS was on MEL; it would be considered inoperative). In the procedures on the MEL it states to 'use extra caution when severe winds are reported gusting 20 knots or more' (which they were). However; in the actual MEL under section 5 it states; 'takeoffs and landings are not conducted in known or forecast windshear conditions.' I reported to the dispatch manager stating that I had to use the more restrictive condition (i.e takeoff and landing not conducted) when planning the flight as there was conflicting information. He proceeded to 'explain' to me that a fault had occurred somewhere within the GPWS and that because the windshear mode was not specifically on MEL it was functional. I told him that I was still uncomfortable with dispatching the flight as the entire GPWS system was on MEL. He then proceeded to tell me; 'then you need to find someone else to dispatch the flight and go home.' I could not find any other dispatcher that would dispatch the flight; so I conferred with a fellow pilot; who explained the GPWS logic to me and I dispatched the flight. In short; I felt my job was on the line and I dispatched the flight. Subsequently before departure; the GPWS was fixed and removed from the MEL on the aircraft. My suggestion to prevent a recurrence to this situation is a rewording of the MEL (to remove conflicting information). Add a portion to the MEL stating 'ground proximity warning system fail status message (with limitations for dispatch)' as well as a company flight manual reference to ensure that the limitations for windshear are clearly stated when the GPWS is on MEL. In the pilot handbook; all of the windshear avoidance maneuvers include the use of the GPWS as it triggers the aural windshear warning. As the GPWS was on MEL (all functions inoperative) that would mean that I shouldn't have planned on using any function of the GPWS.

Original NASA ASRS Text

Title: A CRJ700 Dispatcher reported that a MEL making the GPWS inoperative also made the Windshear Warning inoperative and so the aircraft could not be dispatched into known windshear conditions. The Reporter's Manager disagreed and forced the Dispatch Release.

Narrative: A FAR 121 Dispatch Release was cued for dispatch on aircraft. After reviewing the MEL for that aircraft; I found there is conflicting information regarding the GPWS Windshear function (as the entire GPWS was on MEL; it would be considered inoperative). In the procedures on the MEL it states to 'use extra caution when severe winds are reported GUSTING 20 knots or more' (which they were). However; in the actual MEL under Section 5 it states; 'Takeoffs and landings are not conducted in known or forecast windshear conditions.' I reported to the Dispatch Manager stating that I had to use the more restrictive condition (i.e takeoff and landing not conducted) when planning the flight as there was conflicting information. He proceeded to 'explain' to me that a fault had occurred somewhere within the GPWS and that because the Windshear Mode was not specifically on MEL it was functional. I told him that I was still uncomfortable with dispatching the flight as the entire GPWS system was on MEL. He then proceeded to tell me; 'then you need to find someone else to dispatch the flight and go home.' I could not find any other dispatcher that would dispatch the flight; so I conferred with a fellow pilot; who explained the GPWS logic to me and I dispatched the flight. In short; I felt my job was on the line and I dispatched the flight. Subsequently before departure; the GPWS was fixed and removed from the MEL on the aircraft. My suggestion to prevent a recurrence to this situation is a rewording of the MEL (to remove conflicting information). Add a portion to the MEL stating 'Ground Proximity Warning System Fail Status Message (with limitations for dispatch)' as well as a Company Flight Manual reference to ensure that the limitations for windshear are clearly stated when the GPWS is on MEL. In the Pilot Handbook; all of the windshear avoidance maneuvers include the use of the GPWS as it triggers the aural windshear warning. As the GPWS was on MEL (all functions inoperative) that would mean that I shouldn't have planned on using any function of the GPWS.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	883101
Time
Date	201004
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Regional Jet 700 ER/LR (CRJ700)
Operating Under FAR Part	Part 121
Flight Phase	Parked
Flight Plan	IFR
Component
Aircraft Component	GPWS
Person 1
Function	Dispatcher
Qualification	Dispatch Dispatcher
Experience	Dispatch Dispatch 5.5
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural MEL

A CRJ700 dispatcher reported that a MEL making the GPWS inoperative also made the windshear warning inoperative and so the aircraft could not be dispatched into known windshear conditions. The reporter's manager disagreed and forced the dispatch release.