My colleague Christian Lowe at DefenseTech has gotten his hands on an investigation report into a fire that nearly destroyed an MV-22 in November during a training flight near New River, N.C. Here's his story:
[NOTE: Picture is a scan from one provided in the investigation report]
Turns out, the fire sparked after the #3 hydraulic system ruptured due to pressure spikes from the engine air particle separator which filters inlet air before it is ingested by the engine. The hydraulic fluid spilled all over the IR suppression system, igniting the left nacelle into a ball of flame. The pilots and crew landed safely but the nacelle was a melted, twisted hulk. It caused $16 million in damages.
The crazy part is that this is a known problem. Our friend Bob Cox of the Ft. Worth Star Telegram has reported this same rupture before and his sources in the maintenance community indicate to him the problem is much worse than the Corps admits. In fact, the report shows a Airframe Change notice (#88) that calls for the installation of thicker hydraulic tubing in the EAPS system because of known pressure spikes that can cause a "catastrophic failure." That notice came out in August, three months before the November incident.
The Corps (an Navy) told us not to worry, this was a problem on the Block A aircraft and the retrofits would go on those. Problem is, the November fire happened on a Block B Osprey. [Turns out this was a Block A.]
Christian is giving the Corps a chance to respond, so you won't see the final version of the story yet. If you know something, feel free to email me directly. My address is firstname.lastname@example.org. Let us know how serious you think this issue really is.