by Robert L. Sumwalt

It's no secret. When a flight crew's attention is diverted from the task of flying, the chance of error increases. Over the years there have been dozens of air carrier accidents that occurred when the crew diverted attention from the task at hand and became occupied with items totally unrelated to flying. Consequently, important things were missed. Things like setting the flaps prior to takeoff, or extending the landing gear before landing. Things like monitoring altitude on an instrument approach, or using engine anti-ice for takeoff during a blinding snow storm.

In 1981 the FAA enacted FAR 121.542 and FAR 135.100 to help curb the number of these accidents. Commonly known as the "sterile cockpit rule," these regulations specifically prohibit crew member performance of non-essential duties or activities while the aircraft is involved in taxi, takeoff, landing, and all other flight operations conducted below 10,000 feet MSL, except cruise flight. (Click here to go to FAR 121.542 and 135.100 .)

It's unrealistic to expect a crew to fly together for several days and never discuss anything except items related to flying the aircraft. In fact, experts have demonstrated that in order to be most effective, crews need to talk -- even if it is just merely "get to know you" sort of chat. The sterile cockpit rule is a good rule because it clearly defines when it is time to set aside non-essential activities and tend strictly to the task at hand -- that of safely operating the aircraft.

In spite of the existence of the sterile cockpit rule over the past decade, pilots have continued to have accidents and serious incidents that perhaps could have been prevented. For the most part, disobeying the rule is not intentional. It just happens. But as this review shows, the consequences of non-compliance can be very serious. Truly, the sterile cockpit needs to be cleaned up.

This reviewer used the ASRS database to find specific examples of problems related to non-compliance with the sterile cockpit rule. We carefully reviewed 63 reports that had been previously coded by analysts as having some relevance to the sterile cockpit rule. Here is a synopsis of the problems that we found that could be attributed to sterile cockpit violations:48% were altitude deviations

14% were course deviations

14% were runway transgressions

14% were general distractions with no specific adverse consequences

8% involved takeoffs or landings without clearance

2% involved near mid-air collisions due to inattention and distractions.

The Culprits

The way in which the sterile cockpit rule was broken in each report was tallied and analyzed. Some reports contained more than one culprit. Many of the reports contained acknowledgments like this:

• "If we [had] adhered to the sterile cockpit, this situation probably would not have occurred." (ACN 118974)

Following are the four most common reasons for non-adherence to the sterile cockpit rule:

Extraneous Conversation

The most habitually cited offense was extraneous conversation between cockpit crew members. Cited one First Officer:

• "Although VMC on the approach, the new special weather was... [indefinite ceiling, 200 obscured, visibility 1-1/4 mile in ground fog], snow falling and some snow on the runway...I was flying and Captain viewing PIT stadium and various sights out the window, chatting incessantly...Captain then reviewed procedures for short ground roll on snow covered runways and returned to miscellaneous conversation." The crew believed that they then landed without contacting the tower and receiving landing clearance. After some serious soul searching, this reporter continued "...the potential for disaster scenarios should be apparent...The bottom line: lack of professionalism. Captain habitually rambled from push back to block-in through a four day trip. This was the first of two incidents on the same day...Below the line: lack of courage. F/O and F/E were not willing to ask the Captain to please shut up so we could fly the airplane." (ACN 102595)

The Captain of an air carrier aircraft admits to conversation not pertinent to flying duties:

• "...Both the F/O and I became distracted because of a conversation that was started before the level-off. At 4300 feet our altitude alert system went off...Our sterile cockpit procedures should have eliminated this problem if properly followed." (ACN 168474)

Five reports detailed extraneous conversation with jump seat riders. The ability to ride on an air carrier's jump seat is quite a valuable privilege, but it is important that the additional cockpit rider not be allowed to create distractions. A look at two of these reports:

• "While descending into a broken deck of clouds, unannounced traffic appeared at 12 o'clock and less than a mile, climbing up our descent path. In my best estimation we were on a collision course. I immediately, without hesitating, instinctively pushed the aircraft nose down and to the right to avoid impact. The Captain was engaged in a conversation with [somebody] on the jump seat." (ACN 167026)

And in the other ASRS submission:

• "This very senior Captain was about to leave on a Scuba diving trip and talked nonstop to the female jump seat rider upon discovering she was also a diver...This [altitude deviation] could have been prevented entirely if this particular Captain...[had paid] attention to his job and observe[d] some approximation of the sterile cockpit below 10,000 feet." (ACN 119289)

The connotation "extraneous conversation" does not always have to imply just those persons on board the aircraft. Look at how extraneous chatter with air traffic controllers introduced problems for these crews. Air traffic controllers, take notice:

• "We turned base to final. Tower talked about mutual acquaintances and local weather. On final, at about 2500 MSL, we realized we lined up for the wrong field...First mistake: getting involved in conversation with [the] Tower operator..." (ACN 108035)

And in another incident:

• "At the outer marker...with thunderstorms in progress, reported wind shear and heavy rain ...the tower insisted on knowing if our gate was open. We told him we were too busy to find out, he persisted with claims of needing to know where to put us on the ground once we landed. We attempted once to try to contact the company but failed due to frequency congestion... We were distracted by the tower's request for non-pertinent info during the sterile period... This [practice]...(of the controller needing to know if a gate is open at the most intense and critical phase of flight) must not be continued. It is an unsafe practice and deters us from conducting a safe flight." (ACN 114244)

Distractions from Flight Attendants

Distractions caused by flight attendants visiting the cockpit or calling on the interphone were noted in almost one quarter of the reports in our data set. This was our second highest source of deviation from the sterile cockpit rule.

• "As aircraft approached Runway 18, Flight Attendant 'A' entered cockpit with coffee for the crew. Crew attention momentarily diverted...Aircraft penetrated hold line approximately six feet for Runway 18...Small single engine aircraft on final for Runway 18 was instructed to go around by Tower...Probable cause of this was short taxi distance to hold line and crew's interruption by [the] Flight Attendant." (ACN 149054)

In another incident, the crew was surprised when they lined up with the wrong runway -- and doubly surprised when they noticed they were in an unplanned formation with a jet landing on the same runway!

• "...Flight Attendant came into the cockpit and asked what gate we were going into as we had a passenger with a wheelchair going to another flight...I advised approach we had our traffic [in sight]. Approach now cleared us for what I thought was a Runway 26L visual approach, call tower at the outer marker. As we proceeded to Runway 26L, which was the closest runway to our arrival side,..I looked over [at] my First Officer and out his side window and saw the [other jet] at our altitude, approximately 100 feet away...I'm sure that, with the Flight Attendant interruption, I heard what I expected to hear, 'cleared to the left runway.' " (ACN 98883)

Non-Pertinent Radio Calls and PA Announcements

Several reports we examined indicate that problems arose when non-pertinent company radio calls and PA announcements were made below 10,000 feet. Remember, below 10,000 feet if it's not directly related to flight safety, it's in violation with the sterile cockpit rule.

• "Beautiful day making approach into familiar station, Captain elects to make a PA announcement to passengers while flying the aircraft. Resulting distraction of the passenger announcement [caused us to over-shoot]... altitude 500 feet." (ACN 54741)

While being vectored in a busy terminal area, the Captain in the followi