Date: 201407
Local time of day: 1201-1800
Location: ZDV.ARTCC, CO
Flight conditions: VMC
Light: Daylight
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZDV
ATC / advisory: Center ZDV
Second aircraft: Large Transport
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Distraction; Confusion
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control; Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Separated Traffic; Flight Crew Returned To Clearance
Contributing factors: Procedure
Primary problem: Procedure

Narrative: Weather balloons were being reported in the AKO VOR area.  Reported by multiple aircraft.  First report was at FL350.  Next at FL310.  Next at FL410.  These weather balloons were reported in sight (during visual meteorological conditions) and multiple aircraft were able to visually separate themselves from these weather balloons.  We had no report showing us that weather balloons were going to be launched.  This happened during the busiest departure rush of the day in the middle of the busiest departure gate out of D01.  Through reports from the pilots; we were able to know of three weather balloons that were in the path of the eastbound departures and all overflights.  Reports from the pilots also indicated that they were able to have visual on the balloons from about 15-20 NM out; reporting that the balloons were at least 100 feet wide.  I had experienced a similar scenario while as a CPC on Sector 28 in ZDV.  A report had been turned in for that event as well.  After investigating the regulations on weather balloons; I have been told that they are not required to have a transponder on the balloon and are also not required to even notify ZDV of the balloon launches.  The simple matter is; these balloons are a significant hazard to aircraft.  The balloon itself; along with the radios; payload it carries; can (and will) cause damage if it comes into contact to an airplane traveling at 300 knots. The payload will certainly cause structural damage; and the 100 foot wide balloon could cause some structural damage as well.  If anything were to be ingested by a turbine engine; that engine would immediately fail. These balloons are big enough to be ingested by multiple engines of the same aircraft.  Pilots on IFR flight plans (especially those operating within Class A airspace; which is designed to be 'sterile' airspace; with no VFR traffic) should not be expected to miss a balloon by visual means.  These aircraft are on IFR flight plans and need to be treated as if they are flying in instrument meteorological conditions; because they have every right too.  We as controllers are not allowed to use visual separation in Class A airspace; so why should we expect pilots to separate themselves visually from a 100 foot weather balloon in class A airspace?  It is a scenario that can be easily be looked down upon; and seen as insignificant.  This is a real problem; and has the potential to cause significant damage to aircraft that are expecting to fly through 'sterile' airspace under instrument flight rules. Recommend that all weather balloons have to be reported to the affected facilities.  All weather balloons must also be required to have a mode C transponder on board so ATC can have the ability to separate airplanes from the weather balloon.




Synopsis: ZDV Controller describes situation where weather balloons are reported by airborne aircraft.  The controller was not aware that the balloons were there until reported by the pilots.