Narrative:

While cruising at FL330, with live horses as cargo, we experienced moderate turbulence. The first officer (PNF) was in the lavatory. The captain received clearance to climb to FL350. Approaching FL350, the captain canceled the altitude capture mode and selected vertical speed in an effort to smooth the level off for the horses. I was unaware that he had deselected altitude capture. At approximately FL360, center queried us on our clearance, then asked if we would like to continue to FL370. The captain declined and descended to FL350. The following appear to be factors in this incident: nonstandard cargo: horses, nonstandard procedure by the captain in an attempt to protect the cargo, distracted attention by captain and so during level off, FMS design in dc-10 that gives no alert of altitude deviation in the vertical speed mode. Supplemental information from acn 272490: I believe that a light should blink or a horn should be activated in the event of exceeding the altitude alerter rather than just blindly being able to climb right out of the sky until noticed. (In fact, if you leave a selected altitude, a light does blink until manually canceled.) if a manual vertical speed climb can cancel the automatic leveloff portion of the autoplt, I feel it is extremely important to investigate adding a feature to the autoflt system that should tell you when the aircraft has exceeded what you have set in the windows. I also believe that flight departments should train their pilots to bring in the 3RD crew member of a 3-MAN cockpit into the 'front end' picture when a front end pilot has to excuse himself from the cockpit for physiological reasons.

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Original NASA ASRS Text

Title: ALT BUST.

Narrative: WHILE CRUISING AT FL330, WITH LIVE HORSES AS CARGO, WE EXPERIENCED MODERATE TURB. THE FO (PNF) WAS IN THE LAVATORY. THE CAPT RECEIVED CLRNC TO CLB TO FL350. APCHING FL350, THE CAPT CANCELED THE ALT CAPTURE MODE AND SELECTED VERT SPD IN AN EFFORT TO SMOOTH THE LEVEL OFF FOR THE HORSES. I WAS UNAWARE THAT HE HAD DESELECTED ALT CAPTURE. AT APPROX FL360, CTR QUERIED US ON OUR CLRNC, THEN ASKED IF WE WOULD LIKE TO CONTINUE TO FL370. THE CAPT DECLINED AND DSNDED TO FL350. THE FOLLOWING APPEAR TO BE FACTORS IN THIS INCIDENT: NONSTANDARD CARGO: HORSES, NONSTANDARD PROC BY THE CAPT IN AN ATTEMPT TO PROTECT THE CARGO, DISTRACTED ATTN BY CAPT AND SO DURING LEVEL OFF, FMS DESIGN IN DC-10 THAT GIVES NO ALERT OF ALTDEV IN THE VERT SPD MODE. SUPPLEMENTAL INFO FROM ACN 272490: I BELIEVE THAT A LIGHT SHOULD BLINK OR A HORN SHOULD BE ACTIVATED IN THE EVENT OF EXCEEDING THE ALT ALERTER RATHER THAN JUST BLINDLY BEING ABLE TO CLB RIGHT OUT OF THE SKY UNTIL NOTICED. (IN FACT, IF YOU LEAVE A SELECTED ALT, A LIGHT DOES BLINK UNTIL MANUALLY CANCELED.) IF A MANUAL VERT SPD CLB CAN CANCEL THE AUTOMATIC LEVELOFF PORTION OF THE AUTOPLT, I FEEL IT IS EXTREMELY IMPORTANT TO INVESTIGATE ADDING A FEATURE TO THE AUTOFLT SYS THAT SHOULD TELL YOU WHEN THE ACFT HAS EXCEEDED WHAT YOU HAVE SET IN THE WINDOWS. I ALSO BELIEVE THAT FLT DEPTS SHOULD TRAIN THEIR PLTS TO BRING IN THE 3RD CREW MEMBER OF A 3-MAN COCKPIT INTO THE 'FRONT END' PICTURE WHEN A FRONT END PLT HAS TO EXCUSE HIMSELF FROM THE COCKPIT FOR PHYSIOLOGICAL REASONS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.