Pilots sometimes take weight
and balance matters for granted, especially with a familiar aircraft
or an "average" payload. A general aviation pilot, overestimating
the aircraft's performance and underestimating the passenger load, reports
on the effects of an overweight takeoff in a six-place airplane:
- Accelerated
to full power, 10 degrees flaps, and rotated at 70 knots. Pulled gear
up at approximately 10-15 feet in the air. Sank into the ground at
full power, in effect a gear-up landing. After the incident, the aircraft
contents were weighed, and actual weight was such that the aircraft
was 150 lbs. over gross. I had previously removed the two rear seats,
and had estimated the weights.
Clearly, I should have weighed each of my passengers and their bags.
Also, I only guessed about the amount of weight savings that removing
the two rear seats would produce.
Pilots also need to consider
the trade-off between the performance gained by "cleaning up"
the aircraft immediately after takeoff versus the safety of leaving
the gear in place until there is no longer a chance of the aircraft
settling back onto the runway. Additionally, on some aircraft the gear
doors open to allow gear retraction; this temporarily increases drag
and decreases lift, reducing aircraft performance.
The
Bod Squad
Air carrier crews can find
their aircraft overloaded when cabin weights are incorrectly calculated
- or estimated - by company dispatch. A Captain tells of the flight
of his "heavy" aircraft, a B-727 laden with a football team.
- The aircraft
papers indicated that the aircraft would be just 100 lbs. or so below
its maximum structural gross weight for takeoff. Takeoff was done
with an abnormally long ground roll, and climb performance was marginal
both dirty and cleaned up. Flight was planned for FL310. At about
FL260, rate of climb was less than 500 feet per minute. The aircraft
could not make it to FL310 and stayed at FL260. When I rechecked the
weight and balance, I saw that we had 100 passengers, and that "normal"
passenger-plus-carry-on weight of 212 lbs. was used to calculate cabin
weight. I watched these guys disembark; they are gigantic, and all
carried very large equipment duffel bags. I think the aircraft was
a good 8,000-10,000 lbs. over planned weight, and far in excess of
structural gross weight.
Abnormal passenger loads - troops, football teams, sumo wrestlers,
etc. - should require actual weights for dispatch.
The reporter's point is relevant
to both the previous report and this incident: the use of "average"
weights for passengers, luggage, and carry-on items can lead to gross
inaccuracies in calculating gross weight.
Hurry
Up and Weight
In the rush for a quick departure,
this air carrier crew apparently overlooked the takeoff weight limitation
for their assigned runway. The First Officer reports:
- After
pushback, we began to taxi and the Captain elected to shut down one
engine to conserve fuel. It turned out to be a short taxi, so he instructed
me to restart the engine. There was not much time between checklist,
taxi instructions, and watching for traffic and taxiways at this busy
airport.
The flap and power settings for our calculated takeoff weight are
printed on the Automated Weight and Balance that the computer generates.
I selected and informed the Captain of the flap setting and power
required, but failed to notice that the performance criteria were
designated for Runway 4R and we were cleared for Runway 4L, which
is considerably shorter. On takeoff roll, it was somewhat evident
that the end of the runway was coming up fast. We departed without
incident, and realized the mistake while enroute.
Neither of us had checked the runway that the takeoff weights were
predicated on. We were 10,000 lbs. overweight on our departure.
When faced with schedule
pressures or other time-related constraints, flight crews need to take
an extra moment to ensure that potentially critical information does
not pass unnoticed.
Keep
The Big Picture
An air carrier pilot provides
a final thought:
- Each trip
I gain some sort of new experience. Isn't that what makes flying great?
Fly the airplane. Keep the big picture. Think ahead. Don't rush your
thinking. Use your crew as a team. Lead the team. And read CALLBACK,
of course!
Many of the "flight
assist" stories that ASRS hears about involve observant ATC personnel
who come to the aid of pilots in trouble. Sometimes ATC gets help from
other sources - as in the case of this general aviation training flight
that suffered a loss of engine power over unfriendly terrain, at the
approach of dusk.
- After
an uneventful training flight with multiple touch-and-go landings,
we climbed up to 3,500 feet MSL and started back. Just as we were
recovering from a practice approach-to-landing stall (power-off stall),
at the point of power application, the engine made a loud sound and
began vibrating. As we had previously practiced simulated engine failures,
I had my student check [the engine failure checklist], and I called
Tower, informing them I had a partial power failure, was declaring
an emergency and heading direct for the airport. We were about 15
nm West-Northwest, and the Tower gave us a squawk code and asked if
I thought I could make it to the airport. I said I would decide at
the last suitable off-airport landing site (a reservoir/dry wash which
I knew had 2 dirt roads). Having lost 1,000 feet in about 5 miles,
I told Tower I was landing in the reservoir and requested assistance
in case things didn't work out.
By the time I turned base for a dirt road I could barely make out,
a police helicopter arrived and lit up a landing area and a tree I
was able to avoid before touchdown. There were a few scratches from
bushes I scraped, but otherwise no injury or damage. One spark plug
was found missing and was replaced....I may have been able to make
it to the airport on the night of the occurrence, but elected to land
off-airport.
Contributing to superlative
efforts by the police helicopter and ATC, this flight instructor earns
a "well done!" for clear communications and cool decision-making
under pressure.
"Getting
There" Was An Experience
In another nighttime emergency,
this one experienced by a corporate flight crew, all ended wellbut
getting there was an isolated and frustrating experience, especially
for the Captain.
- We made
a normal nighttime departure. We had just been handed off to Center,
level at 14,000 feet MSL, when I noticed a peculiar distorted appearance
to the instruments. I smelled smoke at the same moment that I was
pointing out the weirdness to the co-pilot. Smoke is not instantly
visible in a dark cockpit. ATC was immediately advised. They cleared
us direct [to return] and down to 12,000 feet MSL. They then said
to contact Approach. So far so good. Then I told the co-pilot to put
on his oxygen mask as I donned mine. As I did this, I [knocked] my
headset off, but I didn't realize it. I selected 'Mask' on the comm
console which allowed me to communicate with ATC. My co-pilot changed
frequencies and communicated with Approach. He heard them clear us
to 4,000 feet MSL. I heard nothing. No cockpit talk, no ATC. I then
remembered that I needed to select 'Cockpit' on the comm console so
that he [co-pilot] could hear me by way of a 'hot' mike set-up. I
asked him if we had been cleared any lower. He answered, but I couldn't
hear him. I was isolated and frustrated. I pulled my mask off and
told him I couldn't hear him. He punched on his hot mike about the
same time I realized I needed to go to the 'Speaker' to hear anything.
We were back in business....Positional awareness was excellent. #1
nav had fried internally and was the source of our smoke, #2 nav did
the trick. Now I could see the well-lit terminal complex but no runways.
We requested that the Tower turn up the runway lights which they did
after a few seconds. It was wonderful: Orientation was complete. ATC
might want to do this as a regular part of night time emergency procedures.
The usual low runway lighting is extremely difficult to pick out against
the background of normal city and terminal area lights. Finally, the
airport Crash-Fire-Rescue (CFR) personnel were excellent in helping
us safely explore what had burned and in confirming the problem was
over.
This flight department is now operating on the assumption that we
will lose our headsets and must go to speaker in a similar situation.
This crew's experience highlights
the need for training in equipment familiarity (oxygen mask and communications
radios) in a darkened cockpit. The Captain's suggestion about turning
up the runway lighting is also one that ATC facilities may want to consider
in reviewing their night emergency procedures.
The
Bottom Line...
A general aviation pilot
was persuaded by a business associate to undertake a flight into known
icing conditions, against his better judgment. After a harrowing in-the-clouds
icing experience, an emergency declaration to ATC, and an unscheduled
landing, the pilot humbly reported this new resolution to ASRS:
- I've
flown enough to know when it will be bad. I've flown enough to make
good rules. Now I just need to abide by my own rules. When I say "it
looks bad," I should stay on the ground.
