Robinson R22 – Hole in Engine Cooling Sheet Metal

Submitted by: AK

Looking underneath the firewall to see the top of the engine cowling, POV is from aft of the caution light test buttons. Other photo is looking up through the shroud having removed the fan shroud. It could also have been seen should the pilot looked up through the oil cooler around at more than just the cooler itself. This helicopter was used in a training school, and during the first circuit of the day while conducting pre-landing checks found the oil temp to be up at the red line. Immediately landed and the temperature dropped down, hovered a bit, seemed fine, flew a half circuit because the temp once again red lined. Shut down for a thorough look over and discovered this.

Additional Photos

Maintenance Notes

Outcome: Grounded

Origianally we thought it was a blocked oil cooler or that there wasn't enough air going through the cooler due to dust. On removing the cooling fan shroud, it became very obvious what was wrong. The cooling air from the fan was escaping up through the whole rather than down through the cooler, leading to temperature increases in CHT and oil. It required replacement of the engine shroud and a rebalancing of the cooling fan. The imbalance of the fan caused a vibration that started the crack which then circled back on itself (refer photos).

These notes reflect reported observations at the time of submission and are provided for educational purposes only. They are not a determination of airworthiness and do not constitute maintenance or regulatory advice.

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