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Angier and I had the following discussion off list. For those of you who
haven't heard my agony here's one way to loose a year and a half of good
flying. This story is about my IO360 LNC2 which had 11 months and about
110 hours on it at the time. This one you won't find under an NTSB report. Two lines of demarcation
regarding NTSB reporting according to AOPA and EAA at the time were:
1) Was there damage to the airfield? 2) Was there a 911 or EMS called? In my case the answers were both no (my airport manager thought the
little tick marks in the runway to be irrelevant).
Safe flying! Larry
"Along these lines it'd be great to have a SB informing folks to
calibrate their "safety" squat switch. Mine went down the runway set at
68 kts. Darn."
Hi Larry,
Did this result in any damage?? Hope not.
Is this switch adjustable and if so, what airspeed did you use?
Larry Henney wrote:
Yes Angier,
My builder, pilot, and mechanic (me, me, and me again) all helped out
in sending my father, my son, and I to the runway in a foolish hurry with the gear handle up. The switch actuated just as advertised in the Lancair catalog (or a kt or two slow, I forget). I think it was originally designed for 235 speeds and gross weights. Anyway, the gear retracted just prior to rotation at full power and max gross weight (perhaps an 80-85 kt liftoff speed).
$30K later, I rebuilt it firewall fwd, gear doors, center belly
section. Much angst and humiliation.
Don't make my mistake of not checking the set point if you have one.
I now have it set at about 1.3 Vs or 90 kts. I think I could squeak it back to 85 without much fear. Much lower would increase the risk dramatically.
OUCH!
I know this is a really stupid question but, ....why was the gear handle
up prior to rotation?
Angier,
The longer version goes like this. Father, Son(builder, mechanic, and
pilot), and grandson showed up to go fly and found a dead battery. The
builder failed to make convenient access to his battery for charging.
The battery is located on the firewall. The cowling has piano hinges.
Thus, actually starting the plane cowl off is a bad idea for cowl
reinstall while engine running (and subsequent charging).
Mechanic (smart guy) jumps in here and suggests that there are heavy
gauge wires in the passenger seat back providing power to the hydraulic
power unit. These feed the battery and could conveniently be used for
charging the plane. And so it goes. Open seat back, connect battery
charger. Begin charging. Clickety, clickety, clack. For some reason
the hyd unit was cycling on and off with power on the charger. At one
point I had a more direct reason for the clickety clack. I'm a little
unsure, but perhaps it was the need for more down pressure amidst the
need for amps to drive the motor. A little pressure bleed down after
the plane sits for awhile is normal. The pump will momentarily chirp
recharging the system following turn on of the master.
Pilot (smarter guy) jumps in here and suggests, "well for maintenance
you can take the hyd unit control power off line by raising the gear
handle". Why, you ask? Because we're not moving and the pitot safety
squatch switch requires 70 kts (actually 68) to operate the gear. So,
the 3 of them (builder, pilot, and mechanic) decide it'll be an easy
fast way to charge the battery. Vroom. The plane is started (long
after the preflight checklist was completed-remember check gear handle
down). The pilot jumps in while father returns charger (3 yr old son
already installed in jump seat) and pilot holds brakes while replacing
screws in seat back access panel. (pilot a little not thinking of flying
toy airplane at this point). (Did I mention, pilot needs to catch two
jumpseats to get from Fresno to Miami later in the day while on
probation with brand new airline job? ... And skipped church to
boot..Never a good idea.)
A short while later following a takeoff checklist father, son, and
grandson are standing beside the rubble and notice the plane sitting a
bit lower than usual. Switch had worked admirably at 68 kts allowing
the nose to retract first. Then following the addition of about 5 more
kts the plane while airborne retracted much of the main gear before
grinding it's way back onto the runway. Twelve dents in the runway were
hardly noticable while the prop tip was virtually folded under after the
subsequent flare (and prang). The rebuilder (smartest guy yet) has now installed a lovely little
Cessna charging receptacle in the passenger seat back (properly
bypassing the hyd unit). Additionally, he adjusted the pitot switch to
90 kts (still a bit higher perhaps than necessary). Finally, added about
30 pounds of glass, foam, and micro to further reduce climb rate and top
speed by a quarter kt. Rebuilder immediately went on a 30 pound diet to
compensate for these performance deficiencies.
Never in the history of the world had I raised (or even considered
raising) a gear handle on the ground. I bought the switch based on the
once in a million chance that one of my 4 devious little rug rats might
inadvertantly raise the handle. Never had it occurred to me that pitot
static switch was adjustable or possibly set too low. It became a
mechanics tool which somehow left the pilot without any cognitive
involvement.
Happy to be here alive to tell you about it. Morals of the story. 1. Don’t be in a rush. 2. Have as many people look over your plane as possible (before and
after 1st flight-mine had over 100 hours on it with this squat bomb
waiting to say hello)
3. Have folks quiz you about possible failure modes and ramifications
prior to strapping it on. 4. Finally, if the unusual (maintenance) ever occurs after any
checklist has begun (flight attendant interuptions for example), have
the pilot return to the first checklist and do it over before moving
forward.
My saga; hope yours isn't this enriching nor humbling.
Larry Henney
N360LH 325 hrs
(think how fast it'd be w/o the rebuild) :(
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