I was going to point out that CC’s facetious example about finding a wrench in a wheelwell was the precise cause of an incident not that long ago with an airliner. The gear got stuck, an emergency landing was carried out, and a lot of damage was caused. The cause? A wrench left in the wheel well. And a few years before that, an engine fell off an airliner because the fuse pins were not installed again after the engine was removed for maintenance.
Kind of makes you wonder how many airline accidents have been averted because something dangerous was found during a walkaround. In this day of 40 billion airline security packages, a walkaround seems like about the cheapest form of safety improvement we have.
Grok: Heh. Maybe it just means that we pilots are useless without a checklist!
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And a few years before that, an engine fell off an airliner because the fuse pins were not installed again after the engine was removed for maintenance.[/qupte]
I mentioned this one in another thread: A student pilot’s landing gear fell off on the first flight after the rental came out of maintenance, because the A&P forgot to put the bolts in. She landed safely. I don’t recall the type of aircraft or if the missing bolts could have/should have been noted on preflight.
I think this thread makes one thing very clear: That pilots tend to be extremely safety-conscious. Sometimes we have lapses in our decision-making, but by and large we are very serious about our hobby or livelihood. A non-pilot may not understand things a pilot does, but there are reasons for them.
How did she know the wheels had come off? Seems to me that once you’re in the air something like that could go unnoticed.
I picked up the habit of checking the gas, undercarriage, mixture and prop before landing, even in a fixed-pitch, fixed-gear 172. For the undercarriage I’d look out the window, see the wheel and say “down and welded.” Nice to know that might have actually come in handy. Now if the right or nose wheel had come off, that could have been trouble.
I had Grumman AA1 which approached at about the same speed as light retractables, even though it had fixed gear. Many times the controller would clear me for final by saying, “Cleared to land, check gear down.” I succumbed to temptation at least once at my home field and gave him the old, “Gear down and welded” line.
The landing gear departed the airframe on takeoff, and she was notified by the tower. (It seems to me it was a low-winged aircraft.)
Yeah, the “down and welded” was part of the GUMP check in the 172 and 182. The GUMP check was modified to GUMCP and GUMCCP for the two aircraft, respectively: Gas, Undercarriage, Mixture, Carb heat, Prop (only RPM) and Gas, Undercarriage, Mixture, Carb heat, Cowl flaps, Prop (high RPM).
The R-22 has a very simple pre-landing check: Trim OFF. (It has a little pull-knob that turns the bungee right-trim on or off.) The 300CB is even easier. Just land it. Of course, when it gets into the mid-70ºs or lower, or if it’s raining, you add carb heat to both helicopters. Gas is either on or off, undercarriage is welded, mixture isn’t touched in flight (no flywheel if you lean too much to keep the engine running :eek: ) and the pitch control is used constantly to fly the things. BTW: whereas a fixed-wing aircraft has plenty of time to cool while taxiing to parking, the R-22 and 300CB are cooled down for two or three minutes before going to idle cutoff. For the 300CB, for example, you run at 2500 RPM for two minutes, then go to 2000 RPM until CHT stabilizes, then close the throttle and switch the clutch to the release position, then pull the mixture to idle cut-off. Mags off, alternator off, battery off after clutch is fully disengaged, all remaining switches off, fuel off.
Getting out of an airplane or helicopter isn’t like getting out of a car, eh?
I have always done one last walk around after doing all the normal oils, fuels, control surface waggles etc.
10 things one can find on a final walk round:
Control locks still in place (I’m sure I waggled those things!!)
Seatbelt hanging out of passenger door with door closed.
fuel caps off.
Build up of ice on wings.
Tow bar still attached to nose gear
An obstacle in the way of your taxi path (ESPECIALLY in a tail dragger)
Baggage door open
Oil hatch open
Cowlings not secured
Aircraft is bent (yes it does happen!)
These are all relatively obvious at a cursory glance, can all be missed/forgotten/interrupted during the detailed pre-flight, most of them can cause serious problems once airborne, the walk round is your last chance to pick em up.
Also, the passengers like to see that someone has checked the aircraft, and that’s probably more important than many people realise.
Yes, the walk-around is traditional. That doesn’t mean it’s unimportant.
There’s a lot of stuff that can’t be seen or checked, but that doesn’t mean the stuff you can see is unimportant. Plenty of examples have been given.
Once, when I was trying squeeze in an after-work flight lesson and was pressed for time I asked the CFI if he would do the preflight if he got there first so if I was delayed we could just climb in and get started. And that’s what happened.
Well, he noticed something was bothering me and asked what was wrong. I said something to the effect that not doing the preflight myself was like going to work in nice clothes but no underwear. Most likely no one else will ever know, but damn it feels strange.
This resulted in a couple weeks of folks asking “got your underwear on?” instead of “done with your preflight?”
Well, I think I do get it now, thank you. What seems to be cursory and redundant may be so in most cases, but it may also turn up something critically important. Of all the things I read in a week, the SDMB is consistently among the most informative. Thanks, boys and girls.
BTW: whereas a fixed-wing aircraft has plenty of time to cool while taxiing to parking, the R-22 and 300CB are cooled down for two or three minutes before going to idle cutoff. For the 300CB, for example, you run at 2500 RPM for two minutes, then go to 2000 RPM until CHT stabilizes, then close the throttle and switch the clutch to the release position, then pull the mixture to idle cut-off. Mags off, alternator off, battery off after clutch is fully disengaged, all remaining switches off, fuel off.