Air Traffic Control (7110.65) | ATC | Effective: | 07-15-99 | Updated: | 04-02-99 |
10-2-4. ALTITUDE CHANGE FOR IMPROVED RECEPTION
When you consider it necessary and if weather and circumstances permit, recommend that the aircraft maintain or increase altitude to improve communications, radar, or DF reception.
NOTE-
Aircraft with high-bypass turbofan engines (such as B747) encountering volcanic ash clouds have experienced total loss of power to all engines. Damage to engines due to volcanic ash ingestion increases as engine power is increased, therefore, climb while in the ash cloud is to be avoided where terrain permits.
REFERENCE-
AIM, FLIGHT OPERATIONS IN VOLCANIC ASH, Para 7-5-8.