Number 296
May 2004
A Monthly Safety Bulletin from The Office of the NASA Aviation Safety Reporting System
P.O. Box 189, Moffett Field, CA 94035-0189

Density Altitude Density Altitude Chart

As summer approaches, temperatures increase and density altitude becomes an important consideration for pilots. High density altitude can affect aircraft in several ways. Wing or rotor lift is decreased. Engine power is reduced. Propeller, rotor, and jet engine thrust are decreased. Degraded aircraft performance results in increased takeoff distance, reduced rate of climb, increased true airspeed on approach and landing, and increased landing roll distance.

Precise calculation of performance data and strict adherence to Pilot's Operating Handbook (POH) procedures are critical for high density altitude operations.

Squeeze Play

This instructor and student used the POH to calculate the rotation speed but neglected to follow the procedure for leaning the fuel mixture. They put their C172 into a spot where there was not enough speed to takeoff and not enough runway left to abort.

In general, when the density altitude exceeds 5,000 feet, normally aspirated engines should be leaned for optimum performance. Follow the POH procedures for specific aircraft and engines.

High, Heavy, Fast, and Fortunate

If an aircraft is operating at the edge of its performance at a high density altitude there is no room for error- even in the cool of the night.

Heavyweight Joins Wheat Watchers

"Oops! Let's try that again," is not something you want to hear from your surgeon. And, as a passenger of a light aircraft departing a high altitude airport, it is not something you want to hear from the pilot after he takes off and settles into a wheat field.

Field Maneuvers

Even a powerful World War II training aircraft can have a hard time when a soft runway is combined with a high density altitude.

Editor's note:

Scott Gardiner of the FAA's Seattle Flight Standards District Office has published an excellent review based upon the density altitude seminars given by National Transportation Safety Board (NTSB) Accident Investigator Kurt Anderson. The article was printed in the May/June FAA Aviation News which is available at:

Controller's Corner

Enhance Your Image

Flight following, although not mandatory, is certainly recommended for aircraft operating VFR in or near congested airspace. A request for flight following alerts ATC to the presence of an aircraft which may not be apparent on radar and can enable traffic advisories (controller workload permitting) to be given to the pilot. If a transponder is required for the airspace in question, then it is incumbent upon the pilot to ensure that the unit is operational and activated. The airborne TCAS (Traffic Alert and Collision Avoidance System) also relies upon transponder signals to identify traffic conflicts. Use of flight following and/or activation of a transponder by the Cessna in this incident could have prevented a Near Mid-Air Collision (NMAC).

Cabin Report

Say Good-bye to Trouble

In the event that inebriated passengers manage to get through the boarding process, sharp cabin crews can prevent in-flight disruptions by removing them before takeoff.

From the Maintenance Desk

Cap It!

Judging from the number of reports submitted to ASRS, the problem of missing or improperly secured engine oil caps is still a concern. Let's get the word out and put a cap on this problem.

ASRS Recently Issued Alerts On...
B737-200 flap carriage spindle failure
Eurocopter 120B main gearbox oil loss
C750 elevator control cable interference
Faded runway hold short lines at a foreign airport
Inadequate taxiway markings at a southern U.S. airport
April 2004 Report Intake
 Air Carrier/Air Taxi Pilots
 General Aviation Pilots