It Seems That Walkarounds are Important

[MIflyer]

Some years ago I was talking to a former WWII RAF pilot who had flown Wellingtons and Dakotas in combat. I said that while I was careful to do a preflight walkaround for the light aircraft I flew that it seemed that same practice would be useless for large complex aircraft that had dedicated ground crews. Can you imagine the pilot asking the crew chief if he had noticed that the No.3 engine was missing?

My friend replied, "No, a walkaround preflight is very important."

He related that one day he saw a Wellington crew climb into their airplane and try to take off. The cloth cover over the pitot tube was still in place. The Wellington simply ran down the runway, the pilot never getting the airspeed indication he needed, went off the end of the runway and wrecked, with heavy loss of life among the crew.

In WWII pilots for large complex aircraft were taught using the "Step 1, Step 2,..." method, using a checklist and performing each required action in turn before going on to the next one. Ideally a pilot should develop skills that enable him to modify the procedures he is using in the event of problems, but wartime urgency usually did not allow that.

One day I was taking off for an hour of dual instruction and noted the ASI was dead around the time I needed to pull back. A bee must have crawled up the pitot tube. It felt right and I had my instructor along, so I took off and we flew an hour with no ASI indication.

 

[soulezoo]

Spiders are especially fond of pitot tubes. In my time I witnessed I don't know how many aircraft returned with the pitot cover melted to the tube because it was not removed prior to flight. Postflight walk arounds can also be illuminating.

I recall one time landing in a C-141 in Windsor Locks Connecticut in preparation of moving a squadron of A-10's to Italy for the Bosnia thingie. We landed, I started my postflight and lo and behold a gusher-- and I really mean gusher-- of jet fuel coming down both the leading and trailing edge of the wing root. This being an airframe with TCTO limitations due to a weak wing box (poor plane only had 46,000 flying hours!) I suspected this was the cause. I found nothing. A fuel cell team from McGuire came up, tore everything apart... found nothing. Put it all back together, fly to Italy, Turkey, Sicily, Azores and home again... no repeat. That still haunts me!

 

[gumbyk]

I once had to do a dual flight with a guys who was purchasing an aircraft and wanted to take it for a test flight before buying it.
The sales person had the plane nicely cleaned and polished, and when I arrived, the guy I was flying with had the plane all pre-flighted and ready to go, so all I had to do was climb in and we were off.
We get airborne, and he says "There's something wrong with the airspeed", and its going backwards as we climb out. I took control and landed, taxied back and checked the pitot.

Turned out when they washed the aircraft, they put a small (1/2" square) piece of tape over the hole in the pitot to stop water getting in - too small for me to see while walking towards the aircraft.

This was in the days before GPS, so we had no speed information, but worse than that, you get into a habit of an instrument scan, and it becomes hard to suddenly ignore one part of that, even when you know its erroneous.

 

[Capt. Vick]

I remember taking my cousin for a flight and during the preflight I couldn't get the stall warning to work. No big deal I thought and off we went. Came back and reported it as a squawk to the owner of the flight school...only to be told it was part of the do not fly equipment list.

 

[MiTasol]

From this fortnights Aviation Human Factors Industry News (to subscribe contact [email protected])
***************
The airline transport pilot reported that he performed a preflight inspection of the airplane before departing on the repositioning flight. The takeoff roll was normal, however, just after the Swearingen SA226 lifted off, he heard a "pop" and felt a vibration. He initially thought that one of the tires had blown, but as the vibration continued, he determined that he might have a problem with one of the propellers. He subsequently returned to the airport in Boise, Idaho, and landed without further incident.
When he shut down the left engine after landing, he noticed that the tip of one of the propeller blades was missing. Further examination of the blade revealed that about 4″ of the blade tip had separated and penetrated the side of the fuselage.
Airport personnel later found additional pieces of propeller blade material on the runway, as well as what appeared to be the blade of a screwdriver and pieces of the handle.
Maintenance personnel reported that a mechanic had been working on the airplane just before the flight and had been called away from the task he was performing before it was completed. The airplane was subsequently returned to service.
The mechanic left a screwdriver on the nose of the airplane in the windshield wiper area, in a position that the pilot could not see. It is likely that, during the takeoff roll, the screwdriver became dislodged from the area of the windshield wiper and hit the left propeller.
Probable cause: Company maintenance personnel's failure to remove a screwdriver that was left lodged in the windshield wiper area of the forward fuselage during maintenance and subsequently became dislodged on takeoff/initial climb and collided with a left propeller blade.
NTSB Identification: WPR17LA078
***************
Other recent preflight stories included abbreviated NTSB report on a G5 crew who did no preflights some 175 times. Killed all on board when they left gust locks in.
Other stories this week