Question about flight Data

I’ve been tracking Virgin America flights 228 and 233 because I will be on them soon. I noticed today both flights have gaps in reporting the usual data such as altitude and speed. Is this some sort of satellite glitch or computers not talking to one another or some other reason?

I guess I’ll try another question. On VRD 233 yesterday, The speed of the plane was 449 at 3;35 p.m., then the graph showed 330 at 3:37 p.m., then again at 3:37 p.m. it was 449. Data glitch of some sort?

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