Descent below Glide-Path

Descent below Glide-Path


NATS reports that recently, several incidents have occurred when aircraft on final approach have descended significantly below the glide path. NATS have in this context issued the following message:


  • Controllers are reminded to ensure that standard phraseology is used when clearing aircraft to descend for final approach.
  • These incidents are not caused by ATC error, but ATC can be very effective in preventing a serious incident from becoming a fatal accident by taking prompt action when it is recognised that an aircraft is dangerously positioned on final approach.
  • If such an occurrence happens on final approach, consider issuing climb instructions immediately, before clarifying intentions or pressure setting.
  • If such an occurrence is noticed by the Tower controller, be prepared to issue immediate missed approach instructions.
  • If such an occurrence is noticed by the Radar controller, following transfer of the aircraft to the Tower frequency, alert the Tower immediately.
  • File a safety report. We can only do something about these incidents if we know about them."

Provisions in ICAO PANS-ATM (DOC 4444) relevant to this type of incident include the following

  • Aircraft vectored for final approach should be given a heading or a series of headings calculated to close with the final approach track. The final vector shall enable the aircraft to be established in level flight on the final approach track prior to intercepting the specified or nominal glide path if an MLS, Instrument Landing System (ILS) or radar approach is to be made, and should provide an intercept angle with the final approach track of 45 degrees or less.
  • In the event an Minimum Safe Altitude Warning (MSAW) is generated in respect of a controlled flight, the following action shall be taken without delay:

a) if the aircraft is being provided with radar vectors, the aircraft shall be instructed to climb immediately to the applicable safe level and, if necessary to avoid terrain, be given a new radar heading;

b) in other cases, the flight crew shall immediately be advised that a minimum safe altitude warning has been generated and be instructed to check the level of the aircraft.


© European Organisation for Safety of Air Navigation (EUROCONTROL) April 2006. This alert is published by EUROCONTROL for information purposes. It may be copied in whole or in part, provided that EUROCONTROL is mentioned as the source and to the extent justified by the non-commercial use (not for sale). The information in this document may not be modified without prior written permission from EUROCONTROL. The use of the document is at the user’s sole risk and responsibility. EUROCONTROL expressly disclaim any and all warranties with respect to any content within the alert, express or implied.


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