Date: 201501
Local time of day: 1201-1800
Location: LGA.Airport, NY
Flight conditions: IMC
Weather elements / visibility: Icing; Snow
Light: Daylight
Aircraft: Medium Transport; Low Wing; 2 Turboprop Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
ATC / advisory: Ramp LGA
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Communication Breakdown; Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: Pre-flight
Result: Flight Crew Took Evasive Action; General Maintenance Action
Contributing factors: Weather; Procedure; Human Factors
Primary problem: Human Factors

Narrative: Inbound aircraft air returned to its departure airport.  We were rescheduled on an aircraft that had been at the gate since the previous night.  In that time about two inches of snow had fallen on the field.  The aircraft was not de-iced prior to our arrival. The aircraft was parked at a ground level gate.  We were instructed to reposition the aircraft to a jetway equipped gate.  During my cold weather preflight of the aircraft I noticed 1-2 inches of snow and ice adhering to all surfaces of the aircraft.  I noticed large amounts of ice and icicles hanging from the leading edge of the wing.  I communicated my observations to the captain and taking into account current weather conditions we decided that de-icing and anti-icing was required prior to departure. The captain communicated with station operations and was informed that all communications with de-ice would be relayed through the operations office.  De-icing was to be done at the gate with the engines shut down and the APU operating.  As the captain began accomplishing other tasks in the cockpit I continued the communications with operations and informed them that a full body type I and type IV application was required. At the conclusion of a normal boarding process we determined that the QRH DEICING checklist was the most appropriate for our conditions.  We accomplished the checklist items line by line and informed station operations that we were configured for deicing.  Shortly afterwards we observed station personnel begin applying a yellow/orange fluid to the aircraft.  Later; what appeared to be the same personnel and vehicle applied a layer of green fluid to the aircraft.  We received communications through the station operations frequency that type I and type IV fluid had been applied and the aircraft was clean of all contaminants; satisfying their duties per FOM.It was at this time I received word that a deadheading crewmember was concerned that the aircraft had not been sufficiently de-iced. Upon hearing of this concern the captain and I discussed our options and quickly determined that we could not dismiss the deadheading crewmember's claim without further investigation.  From the flight deck windows the wing surfaces appeared shiny; clean; and clear of contaminants.  I volunteered to exit the flight deck and speak directly to the crewmember.  Upon reaching the crewmember's seat they informed me that; in their observation out of the window; the wing still had 'slush' adhering to the top surface.  I attempted to look out of the window but visibility was restricted by a layer of yellow/orange fluid.  Unable to see the wing in any detail from the cabin; I returned to the flight deck and requested the main cabin door be opened so I could check the wing directly.  We did not discuss contacting operations to have ground personnel re-inspect the aircraft.  The captain agreed that a close visual inspection by a crewmember was the best option; and I volunteered to exit the aircraft to perform the inspection.  Upon exiting I noticed the aircraft was covered in a mix of yellow/orange and green fluid on the entire fuselage and both wings.  I then walked to the left wing leading edge to begin my examination.  Upon reaching the wing I found that from approximately three feet from the wing root; to approximately nine feet from the wing root; large amounts of up to approximately half inch thick layers of ice adhering to the leading edge and lower surface of the wing.  I then inspected the right wing and found a similar amount of ice on the right wing.  I called the captain out to inspect the wing while I entered the building to communicate with operations personnel directly.  Entering the operations office I heard the captain's voice over the radio discussing the ice adhering to the aircraft.  I directly informed them that the de-icing had; in our opinion; been insufficient and a reapplication of both type I and type IV fluid was required.  I returned to the aircraft; andafter a subsequent de-icing application the aircraft was determined to be clean by the captain and we departed without incident.While the remaining ice that we saw was on a heated portion of the wing; we would not have been operating with the wing anti-ice ON until the final taxi.  I do not know if all of the adhered ice would have been cleared by the wing anti-ice in that time.  I also do not know if areas of the tail or other critical aircraft surfaces not visible from the ground were clear of ice.  This leads me to the conclusion that our takeoff would have been attempted with a wing that was heavily contaminated with ice.  The ground crew erred in both the application and the inspection of the de-ice process.  The ground crew failed at their assigned tasks; and attempted to dispatch an un-airworthy aircraft.I do not know what can be done; personally; to fix this.  We completed all checklists and followed all guidance from our manuals.  As a crew we performed our tasks as assigned.  It would be impractical to have a member of the flight crew exit the aircraft to inspect the de-icing process.  That being said; it is my belief; that had this deadheading crewmember not been paying attention and verbalized their concerns; we had a high likelihood of a catastrophic loss of the aircraft; crew; and passengers. This aircraft; in my opinion; was saved only by a series of events that caused us to cease compliance with standard operating procedures and visually re-inspect the aircraft on our own.




Synopsis: An aircraft parked at the LGA gate overnight had snow and ice on all surfaces. Following Type I and IV fluid application; a deadheading crewmember saw slush and ice still adhering so the process was completed again; satisfactorily.