This past week I had the great pleasure of being delayed on 4 of 4 flights. Just routine these days, I suppose... I was interested in something I overheard while waiting on the jetbridge after landing. The first officer came out and was chatting with the gate agent, and was explaining why the planes were changed. "We had to trade planes with another crew because of weather (in San Francisco). This plane is only VFR, and they took ours out. We had to wait until the fog lifted to leave." Does that make sense to anyone? How can a modern jetliner not have enough redundancy to fly IFR?
Not sure. Perhaps they have a Minimum Equipment List (MEL) that allows them to continue to temporarily fly VFR if one or more IFR-required components have failed?
The pro jet jocks here may have a better explanation, but perhaps they meant they needed to swap aircraft because that particular aircraft wasn't Cat II/III certified, which would be needed to land at SFO if SFO were landing at Cat II/III minimums. I agree that a VFR only jet doesn't seem practical in a commercial air fleet.
Sounds like a good guess to me. Did your flight hit 18,000' MSL (class A)? I can't imagine using a jet for a really short hop where you wouldn't have time to reach a higher altitude. Then again, I'm not an airline pilot...
Does not make sense to me at all without knowing more info? Most 121 ops specs do not allow extended VFR operation for obvious reasons without a ferry permit. Than you would be operating under Part 91 FARS. Some have provisions to take off VFR and pick up an IFR clearance airborne within 50 miles of the departure airport. I have done that before a few times in transport category airplanes. I doubt the whole plane was downgraded to VFR. Even with dual FMC failure there is enough inherit redundancy built in to fly "raw data" IFR. Old school like we all learned. A downgrade from either CAT II or CAT IIIA or B seems plausible without knowing anymore details and assuming the forecasted weather at the destination or alternate required CAT II or CAT III operations. What was the weather like at SFO? If below CAT I they just need a takeoff alternate. SFO you can legally take off with 500 RVR. Triple failure of the pitot/static system does not seem plausible either? or Dual Air Data Computer failure either? The other system could be the IRS if so equipped? You can lose two and still fly into Class I IFR airspace but not Class II, (extended over water or 1 hour out of land based navigation) Delays suck, next time just ask the Captain. He should be open to answer any questions you may have? Cheers
If a component of the anti-ice system is inoperative a commercial jet can be prohibited from flying in potential icing conditions, which pretty much means VMC in the wintertime. Dave
