Number 294
March 2004
A Monthly Safety Bulletin from The Office of the NASA Aviation Safety Reporting System
P.O. Box 189, Moffett Field, CA 94035-0189

Caution: Clear Weather Ahead

Sun & CloudsRestricted visibility. Micro Burst. Icing. Embedded cells. SIGMET. No matter what your affiliation with aviation, certain meteorological terms can evoke a sense of apprehension, even anxiety. But eventually spring arrives, better weather prevails, and forecasts feature a more benign vocabulary. Clear. Light and variable. High pressure. CAVU. Welcome words signal that it's time to relax. Up to a point. If there are any benefits associated with flight operations in hazardous weather, one might be that a certain amount of "adversity" tends to sharpen one's focus, to bring an added level of attention to otherwise "routine" operations. As the following ASRS reports show, clear weather can sometimes have the opposite effect.

Clear Air Compacency

Both of these B737 crews were relaxed and "cruising down easy street." Without the need to stay alert due to weather or traffic, they discovered that a clear, open road can lead to complacency.

  • Beautiful day. Very relaxed; easy approach; no traffic. On initial contact...Tower said that we could land on Runway 2L if we had the airport in sight. Sure, we've got the airport. There's Runway 2R dead ahead, the center field buildings, and the runway on the left. VASI (Visual Approach Slope Indicator) has us high; nose over a little; final flaps; on speed; on glide path. Hmm, I don't remember this power station on final.... On glide path; on speed, lined up; really nice touchdown 1200 feet down the runway. Turn off here at Taxiway T4. T4? The Airport Diagram (10-9 page) shows T4 is on Runway 2C.... Years of flying military and civilian and this is the first time I've done this.... Ground control told us of our mistake but said it was OK because there was no one around! Lucky for us. Nice day. Maybe too relaxed?
  • We were climbing out on an absolutely beautiful day with very little traffic, pretty quiet on the radio, smooth air, enjoying the flying. We did not reset the altimeter from 30.22 to 29.92 passing through FL180. After being level at FL290 for some time, the center controller said, "I've had you 300 feet low for quite a while. Check your altimeter." Oops! We got complacent. It pays to remain vigilant, even on the "easy" days.

Fair Weather Excursion

Spring fever can affect anyone's ability to stay alert and focused. This C172 pilot was just a little out of "sync" and missed a clear opportunity to prevent an expensive mishap.

  • It was a beautiful day after 22 rainy days. I went out to enjoy the sun and upon return, I decided to make a straight-in approach instead of a full pattern. [My] landing checklist for the C172N doesn't say "flaps" and because of the lack of normal pattern procedure, I landed with only 20 degrees of flaps. I was wondering why speed did not decrease. I floated and made a long touchdown. I immediately applied brakes but could not stop in the remaining runway. I ran off the runway and the airplane sustained some damage.... I could not understand why I was floating. I could have, and should have, gone around, but somehow I didn't. It was a beautiful day. I was not mentally alert.

Visual Flight Reverie

Scenic vistas are one of the benefits of the aviation profession, but as this pilot of a light aircraft learned, they can also be a distraction. There is no substitute for a physical checklist, even on the picture perfect days.

  • Approaching for a landing, I determined the active runway from broadcasts by a Learjet preparing to depart. On downwind and base, I observed the Lear's departure and did a mental landing checklist. I did not use the physical checklists available to me in the aircraft. I know of no mechanical malfunction. I either skipped the landing gear item on my checklist, or if I did check, I did not lower the gear and confirm it. The oversight was brought to light by the sound of the airframe impacting the runway.

    The short duration flight and nice weather may have made my attitude more casual than it should have been. The beautiful, low sun with the Learjet departing out over the ocean may have interrupted or distracted me from my mental checklist.... I will always use physical checklists in the future and triple-check gear down. I became more involved in enjoying the view than attending to the business at hand.

Visual Mindset Challenge

Unrestricted visibility led this MD80 Captain to believe that everyone could see what he could see.

  • We were cleared to taxi down Runway 18R, exit at Taxiway W6 and give way to another aircraft on Taxiway W. As we cleared the runway...tower cleared a commuter for takeoff from Runway 18R. I realized at that time that although we were clear of the runway, part of our aircraft would be over the hold short line in order to keep Taxiway W clear. As another aircraft cleared Taxiway W6 I was unsure if the tower wanted us to go north or south on "W" and by then a B737 was cleared to take off on Runway 18R. After takeoff the B737 pilot called the tower to report that [our aircraft] might want to pull a little further off the runway next time. I mistakenly believed the tower was watching the situation and wouldn't clear anyone for takeoff until we had time to clear. I should have immediately called the tower to let him know we might not be clear of the runway. The great weather created a mindset that all parties could see what was going on...

The Voices of Spring

Little Man Whispering in Captain's EarOn mild days in the spring and early summer, the air is filled with the sounds of birds, frogs, and occasionally a little voice saying, "Something's not right." As the people who submitted these ASRS reports found, you can brush off the birds and forget the frogs, but it's a good idea to listen to the "little voice."

A Borderline Decision

The U.S. Customs Border Patrol and the Drug Enforcement Administration keep a close eye on unauthorized border crossings. If these pilots had heeded a warning from "la pequeña voz," they might have avoided an unplanned encounter with the authorities.

  • ...We decided to fly to a small uncontrolled airport at the Mexican border. We had lunch and then we were a bit rushed to get back to ZZZ in Texas.... The geography is such that a straight line back...would cross through Mexican airspace.... We did in fact have current sectionals, an Airport Facility Directory, and IFR charts, but elected to keep the Rio Grande off to our right because it is the border with Mexico. This haphazard method might have worked except that when we came over the Rio Grande we did not recognize it for what is was. We discussed the almost dry "creek bed" below us and felt that the Rio Grande couldn't be that small. We crossed the border.... Knowing that we had entered the [Mexican] airspace, we contacted Del Rio approach control. They didn't seem to care when we gave them a position report. I discussed with the other pilot the possibility that we could be intercepted.... We flew uneventfully on to ZZZ and landed. As we taxied up, several custom agents and police met us. They were friendly and courteous, but also armed. We were informed of the penalties and, after questioning and search, released along with the plane.

    Several lessons: Know where you are going. Have visual landmarks and use all available equipment. We had a GPS and charts. Second, we could have helped the authorities by more clearly articulating to Del Rio approach that we knew were in violation of the airspace and to have them contact other authorities. Finally, when you hear that little voice tell you, "This doesn't seem right," follow it.

Descending Voices

ASRS reports often point out that the "little voice" should be heeded right away. In these reports, an air carrier crew and a solo pilot confirmed the need to act swiftly when the voice calls.

  • Upon check-in with approach, [we were] instructed to cross INTXN at 12,000 feet, then descend and maintain 7,000 feet. The Captain started the descent from 12,000 feet too early. I said we were told to cross INTXN at 12,000 feet. He said that he was sure he heard cross at 10,000 feet. By this time we are descending through 11,500 feet and ATC repeated, "That was INTXN at 12,000 feet, then 7,000 feet." If I had confirmed the clearance as soon as the Captain started the descent, this could have been avoided. I should have listened to that little voice and immediately confirmed with ATC.
  • I was beginning my descent from cruise. ATC cleared me to descend and maintain 5,000 feet. As I was descending through 4,600 feet, ATC told me that he was showing me 400 feet low on his Mode C. He gave me the current altimeter and restated, "Maintain 5,000 feet." I acknowledged my mistake, apologized, and promptly climbed back to 5,000 feet. In my mind I was thinking that I was cleared to 3,000 feet instead of 5,000 feet. There was a moment during the descent that I questioned myself about the altitude. I very nearly asked ATC to confirm the altitude limit, but decided not to. It was only discovered after ATC alerted me to the fact that I was 400 feet below my cleared altitude. Had he not made the comment, I would have descended to 3,000 feet. Why I was thinking 3,000 feet instead of 5,000 is still not clear to me. One thing is clear. There was a moment when the little voice in my head spoke out and I ignored it. In the future I will not hesitate to ask questions and confirm any doubts I have.

Listen to the Solo

This MD80 Captain's "little voice" was not in harmony with the chorus, but it was the only one singing the right tune.

  • During pushback from the gate, we heard a loud bang followed by our aircraft moving backward faster than the pushback vehicle. We were instructed to apply brakes slowly by ground personnel as we had become disconnected inadvertently. After bringing the aircraft to a slow stop, I set the brakes. The ground crew informed us that the tow bar had disconnected, but we were now free to taxi out. Only on my insistence to inspect the nose gear assembly did personnel discover that the pin that holds the towbar to the nose wheel had broken apart and was still attached to the aircraft. Maintenance was then called out to the aircraft to remove the pin from the nose gear assembly. Good lesson in expecting the unexpected during pushbacks and always using that little voice in the back of your mind that's telling you something might be amiss, even when others say everything is OK.
ASRS Recently Issued Alerts On...

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Foreign airport missed approach anomaly

Eastern U.S. airport departure procedure incidents

February 2004 Report Intake
 Air Carrier/Air Taxi Pilots
 General Aviation Pilots