777 Hits Weather Balloon in Cruise
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777 Hits Weather Balloon in Cruise
I suppose it was inevitable.
N775AN, a Boeing 777-200 aircraft operated by American Airlines, was conducting flight AAL139
from London/Heathrow International, United Kingdom (EGLL) to Los Angeles International, USA
(KLAX) with 12 crew members and 273 passengers on board. During cruise flight at FL380
overhead Moose Jaw (CYMJ) SK, the flight crew reported a collision with what is believed to be a
weather balloon. The flight continued to destination and landed without further incident.
The operator’s maintenance conducted a visual external inspection of the aircraft, and no damage
was found. The aircraft was returned to service.
N775AN, a Boeing 777-200 aircraft operated by American Airlines, was conducting flight AAL139
from London/Heathrow International, United Kingdom (EGLL) to Los Angeles International, USA
(KLAX) with 12 crew members and 273 passengers on board. During cruise flight at FL380
overhead Moose Jaw (CYMJ) SK, the flight crew reported a collision with what is believed to be a
weather balloon. The flight continued to destination and landed without further incident.
The operator’s maintenance conducted a visual external inspection of the aircraft, and no damage
was found. The aircraft was returned to service.
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Chance as well as consequence of collision is very limited, so it is deemed to be an acceptable risk. The measurement package is more an issue than the balloon itself.
To be visible, it would need to have a transponder which would add a lot of weight. Alternatively, every aircraft would have to be able to receive and interpret the data the probe is transmitting.
To be visible, it would need to have a transponder which would add a lot of weight. Alternatively, every aircraft would have to be able to receive and interpret the data the probe is transmitting.
Weather balloons already have a transmitter sending a signal every second or so. The US versions send GPS coordinates, pressure, temperature, and humidity. That is more than enough to avoid hitting them. The question is whether it is worth avoiding hitting them. It appears to be less than $100 (less the $15,000 to $50,000 fee for adding to each airplane) or a ground based transmitter could add it as an ADSB target transmission and make them visible to any ADSB-IN system in the related area.
The measurement package is more an issue than the balloon itself
… flight crew reported a collision with what is believed to be a weather balloon …
No damage found, no evidence, no inflight effect on controls or engines.
Visual, or just a belief; who looks out during the cruise - 500 kts closure.
Was it a balloon?
No damage found, no evidence, no inflight effect on controls or engines.
Visual, or just a belief; who looks out during the cruise - 500 kts closure.
Was it a balloon?
Drain Bamaged
More like how many of them Wx balloons (Or else) Went very close and never got noticed.Join Date: Sep 2018
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I used to work on a weather research project, where they were sending balloons up from the airfield twice a day. We had discussions with them about the risk of launching them when there were aircraft in the circuit. They gave us the radiosonde to hold. It was very, very light and encased in a polystyrene 'outer'. That removed all concerns about any collision damage risk. So much so that if we were returning to the circuit as they were releasing one, we would try to 'run into it'! They were never concerned about us doing this and when we said 'surely you don't want us to damage all the work you've put into preparing it for launch' they said 'you'll never hit it' ... and we never did!! (Their initial rate of climb is huge!!) So, if we couldn't hit them deliberately, the chance of an accidental collision should be extremely, extremely low. And, in such an extremely rare likelihood, very much unlikely to cause any damage.
Given the small odds of actually hitting a weather balloon, hitting it just right to ingest the instrument package in the engine would be right up there with being hit by a meteor in-flight...
The weather balloon is entering ADSB mandatory airspace, and doesn't have ADSB out. That seems incongruous. Would be a cost to add, but then it is not needing to be particularly complex to give a useable tracking for the crews.
And, in such an extremely rare likelihood, very much unlikely to cause any damage.
Does the radiosonde return to earth when the balloon breaks? Is it then recovered (that sounds costly and hard work)
Can the radiosonde cause damage/injury when it falls back to earth?
thanks
Can the radiosonde cause damage/injury when it falls back to earth?
thanks
Please look at the image in the post above, #9. The balloon carries a parachute for the payload. When the balloon bursts, the remaining equipment, including the radiosonde, rides the 'chute to earth.
As the sonde transmits position data as a course of it's normal operations, retrievable ones are likely found fairly easily.
As the sonde transmits position data as a course of it's normal operations, retrievable ones are likely found fairly easily.
Last April, over northern Michigan inbound to ORD we passed one pretty close. The F/O saw it first, passed off our left really close, hard to tell. My guess would be less than 100m. There would have been little time for any manuverings. Never saw one of those from the air before. 34-36.000´