Zero-Zero Departure

Current training places too little emphasis on perfecting the instrument takeoff.


Since so much emphasis is placed on approaches during the typical instrument students training, its unsurprising practicing the takeoff into IMC receives little attention. Thats more than a little unfortunate, since the instrument takeoff-especially the zero-zero takeoff-can be much riskier.

For our purposes here, well define the instrument takeoff as one in which the aircraft will be in IMC before reaching the lowest altitude specified for crossing the final approach fix of a published procedure for that airport. Well define a zero-zero takeoff as one where the aircraft enters IMC before reaching DH or MDA on a related approach. Often, of course, the zero-zero takeoff is just that: The crew can see neither the end of the runway nor a definite ceiling, and must transition to instruments when the wheels leave the runway. The challenges posed by either procedure arent immediately obvious to those who havent experienced them, which is another reason for greater attention during initial instrument training.

Takeoffs are always a busy part of any flight, arguably more so than landings. The aircraft is accelerating, for one, and gathering energy that must be dissipated before stopping if theres a problem. Too, panel gauges, especially mechanical gyros, behave in ways further complicating instrument flight when they are accelerated from a standing stop to climb speed in a few seconds. Various procedures necessary during a takeoff and departure-raising the gear and flaps, for example, or setting power-can wreak havoc with a pilots concentration and the aircrafts trimmed attitude. And it is during the initial climb in IMC when any errors in setting the aircrafts configuration are discovered, at exactly the wrong time for something to be done about it.

But, like any other aviation procedure, theres a right way and a wrong way to perform the zero-zero takeoff and minimize its risk. The sidebar below summarizes some tips. Meanwhile, you may want to get together with your double-I for some dual before attempting one. When you do, be sure to think about establishing and maintaining a positive rate of climb as soon as the wheels leave the ground.


On July 3, 2007, at about 0606 Pacific time, a Beech E90 King Air collided with utility lines during takeoff from Runway 24 at the McClellan/Palomar Airport (CRQ) in Carlsbad, Calif. The 57-year-old private pilot and the private pilot-rated passenger were killed; the airplane was destroyed by impact forces and a post-crash fire. The planned destination was Tucson, Ariz.

Instrument conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed. A METAR observation for CRQ at 0553 included calm winds, -mile visibility, fog and an obscured ceiling at 100 feet. Both the temperature and dewpoint were 63 deg. Fahrenheit. The airport is on a plateau, and the surrounding terrain is lower than the departure runway.


After takeoff, the airplanes first identified point of contact was downed power lines an estimated 2500 feet from the departure end of the runway. The airport elevation is 331 feet; the estimated elevation of the line was 245 feet. The debris path was along a magnetic bearing of 270 degrees. The airplane traveled another 50 feet before colliding with the bottom two lines on a transmission tower. The lines were 230,000-volt wires, 1 inch in diameter and located about 40 feet agl. A piece of the right wing was immediately in front of the tower; the right aileron with a section of aileron and the bellcrank remained impaled on the tower about 30 feet up.

The airplane came to rest about 300 yards from the transmission tower with the two transmission lines wrapped around the propeller blades of both engines. The wires were continuous to the wreckage.

Both left and right engines displayed contact signatures to their internal components characteristic of producing power at the time of impact. The engines housings displayed relatively little impact deformation, limiting contact signatures and precluding definitive assessment of their power level at the start of the impact sequence.

The left outboard flap actuator measured three inches, which equates to 12 degrees down. The left elevator trim actuator measured 13/16 inches, equating to neutral.

Probable Cause

The National Transportation Safety Board determined the probable cause of this accident to include: “The pilots failure to maintain clearance from wires during an instrument takeoff attempt. Contributing to the accident were fog, reduced visibility, and the low ceiling.”

Theres nothing inherently dangerous about a zero-zero takeoff (of which we think this is an example): Its risk is higher than one in day VFR conditions but, when performed correctly in a properly configured airplane, is usually successful (just like in day VFR). One source of increased risk comes from failing to perform the necessary configuration. Another involves the possible need to return for an immediate landing if needed. In this case, wed argue the airplane wasnt configured or flown properly. How else can one explain losing 87 feet of altitude less than a half mile from the departure end of the runway?

Yes, there could have been an issue with the flight instruments; the post-crash fire prevented their meaningful examination. There could have been a problem with the engines or with the primary control system, but we all know thats unlikely. Instead, the smoking gun here to us is the elevator trim actuators neutral setting.

As noted earlier, when certain flight instruments are accelerated from, say, zero to 100 knots over a few seconds-especially mechanical gyros-they exhibit certain behavior, namely precession, making them inaccurate for short instances. Non-gyro instruments-the vertical speed indicator, for example-also have characteristics making them unreliable in the first few seconds after takeoff.

Its clear to us the pilot in this accident failed to establish and maintain a positive rate of climb after takeoff. To us, one of the reasons for this was the failure to set the elevator trim for a slightly nose-up pitch attitude. The last thing we want during a zero-zero takeoff is a flat pitch attitude.


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