AIRCRAFT EVACUATION

TCAS TRAFFIC DISPLAY IS NOT RADAR DISPLAY

TCAS in aviation was mandated to facilitate greater situational awareness to the flight crew and serve as a last safety net to avoid mid-air collisions. Over the years, design Improvements in accuracy and response capability of TCAS systems are able to generate Traffic alerts and Resolution Advisories with manoeuvre guidance in case of RAs.

 Of late there have been several reported incidents of crew resorting to pre-emptive manoeuvres solely based on TCAS displays showing traffic proximity. Manoeuvres initiated to achieve self-separation or sequencing, solely on the information displayed on TCAS systems can often result in degraded safety margins and should never be attempted by the flight crew.

 "An A340 reduced its speed on its own, miles too early on approach, to increase the distance from the preceding aircraft [based on the TCAS traffic display]. It messed up the sequence and an A320 was then only 4 NM behind it was obliged to perform an "S" for delay".

A B737 is cleared to climb to 3000 ft. A VFR on an opposite track is level at 3500 ft, but offset horizontally. The controller provides traffic information to the B737. The pilot reports two targets on the TCAS traffic display and shortly after reports a left turn to avoid this traffic. Fortunately, the controller instructs the B737 to stop climb at 2500 ft, because the inappropriate turn reduced the separation.

Examples are many and continue to occur. Regulations on the use of TCAS traffic display at ICAO PANS-OPS Doc 8168, chapter 3, section 3.2, states that “Pilots shall not manoeuvre their aircraft in response to traffic advisories (TAs) only”. This point is also emphasised in ICAO ACAS II Training Guides for pilots. Confusing and nonstandard responses from pilots are also commonly encountered. Responses such as “TCAS Contact” or “We have the Traffic on TCAS”, on receiving traffic information from ATC, provide no added value. 

Flight crew need to appreciate that the TCAS traffic display is not designed to support self-separation manoeuvres, but to aid visual acquisition of an intruder. It gives only a snapshot of the relative horizontal and vertical position of other aircraft in the vicinity. The lack of speed vector and the possibility of rapidly changing relative bearings, it is extremely difficult to anticipate the evolution of the situation based solely on the TCAS traffic display.

Air traffic controllers, on the other hand, base their actions on the comprehensive information shown on the radar display, which enables them to provide a safe and expeditious air traffic flow. The radar display also provides velocity vectors and the controller is able to predictive information of crossing traffic. The TCAS traffic display does not provide the information necessary for the provision of self-separation and sequencing.

When operating IFR in a controlled airspace, ATC is responsible to provide safe separation between traffic. TCAS II is designed to trigger an RA command, should there be a potential or imminent risk of collision between two transponder equipped aircraft. Correct response to annunciated RAs will safely resolve such situations.

If an aircraft is close to its operational ceiling or where the indicated rate climb is excessive, it may simply be unable to follow the RA commands. In these cases, the pilot should continue to manoeuvre at the maximum rate possible consistent with safety and performance. If unable to climb, it may even maintain level flight( engine out conditions).The TCAS equipment in the target aircraft will be able to detect the reduced response and adjust the manoeuvre commands to achieve the desired separation.

Airline operators need to include an unambiguous policy in their Operations Manual procedures, prohibiting self-separation manoeuvres by the crew based solely on TCAS displays.

A330 FUEL LEAK PROCEDURE

A330 Fuel Leak Procedure is best dealt by crew with a background 

understanding of the checklist logic and the system understanding.
Fuel leak on A330 reminds one of Air Transat 236 emergency landing at 
Azores in 2001.

In order to simplify the understanding of this checklist procedure, the same has 
been indicated in flow pattern below in the slides. 
Hope the same is of use to all crew in better understanding of the checklist 
and feel free to write to me with comments and suggestions. 

OVERWEIGHT LANDING

Definition
All aircraft are certified to land at a particular maximum landing weight. Any landing carried out in excess of that weight is termed as an overweight landing.


Design
Landing at or below overweight landing ensures that normal performance margins as per certification are ensured.
Regulatory certification criteria require that landing gear design be based on 

• A sink rate of 10ft/sec at the maximum landing weight, and 
• A sink rate of 6ft/sec   at the maximum takeoff weight.

Commercial airliners normally make a sink rate of 2-3 ft/sec. A so called hard landing barely exceeds 6ft/sec.

When would it be required to carry out overweight landing?

• In case of any uncontrollable fire, damage, malfunction, etc
• In case of crew incapacitation, medical cases on board requiring immediate attention, etc.
• Any other situation where crew perceive an immediate landing is required.

airbus.com

Is it safe to carry out overweight landing?

Enough debates have been done on this subject. Airline crew are trained to handle overweight landing and the performance criteria and design aspects have been catered to allow for such an event should an emergency arise. Overweight landing provision is limited only to non-normal operation and crew shall not land overweight  on a normal flight  due to direct routings and strong tailwinds.

Aircraft are designed with adequate strength margins for overweight landings.Performance margins are generally well above maximum landing weight. Brakes are designed to withstand reject takeoff at the maximum takeoff weight. So oversight landing should not be a problem.

Is there a special procedure for maintenance after landing overweight?

An overweight landing entails a maintenance procedure even if the landing was smooth!!!!!

Inspections aim at checking for structural distress.

Is there a procedure for crew to follow?

Crew have a procedure to follow which aims at sensitizing crew on the sink rate for touchdown and the technique thereof.

Summary

Overweight landing provision is allowed for by the manufacturer in case of exigencies and the procedure is outlined.Design and performance margins allow for overweight landing.Overweight landing is prohibited in a normal operation. Procedures are outlined for the crew and the maintenance teams  to follow in the event of an overweight landing.

DISTRACTIONS & INTERRUPTIONS IN COCKPIT

Why do they occur??

As per Airbus Briefing notes, the following

are the main reasons identified:

·      Communications

·      Head down activity

·      Abnormal condition or unanticipated situation

When do they occur??

They occur during high workload times, such as during pre-flight preparation, taxi for takeoff, approach  preparation, during briefing prior to descent, descent, during approach, and landing phase.

How can it be addressed??

It can be addressed by robust procedures and policies and adherence to them.

During pre-flight, there is a lot of activity around the cockpit and this is the crucial time that the  interruptions due ground personnel, load and trim sheet, fuelling and techlog  activity, cabin crew coordination, passenger boarding,and so on tend to throw the crew away from the task at hand. Thrust should be on regaining the thread effectively from where it was left and pick it up. Most airline procedures advocate going back to the beginning of the checklist to resume, once the checklist is interrupted.
Crew have made errors in entering wrong load sheet data, due to distraction or interruptions, which in some cases have lead to incidents/accidents.

                     

Also, noted is the case of Eastern L1011 crash at Everglades, which was due to distraction of crew from primary task due to landing gear light bulb malfunction.

What are industry line of defense to counter this??

• ·     Company SOP
• ·     Company policy
• ·     Effective communication
• ·     Sterile cockpit below 10,000ft AAL in flight, and during ground operations
• ·     CRM

EXTERNAL WALK-AROUND

Pic of Brussels airlines

FLIGHT CREW AND CABIN CREW COMMUNICATION

Today's cabin crew are highly trained, highly skilled, and centre on safety as the core of their job function. And, just like the pilots, many have been trained in crew resource management principles. However, some recent findings have uncovered some disturbing facts about the division of responsibilities and safety issues between the cockpit (pilots) and the cabin crew (Cabin crew). The underlying goal for both the pilots and Cabin crew is the safe and efficient completion of a flight. Yet, there has been an unrelenting division of these groups in times of emergencies as well as routine operations. How could this be? As a layperson, you would assume that these groups would be highly cohesive by nature, and yet the opposite has been shown to be true.

The problem with pilot and flight attendant teamwork, particularly in the area of communications, has its roots in the disparate job functions of both groups. When speaking of pilots, it is a mostly male dominated profession. Conversely, when speaking of Cabin crew, it is a mostly female dominated profession. It should be noted, however, that there has been an increased percentage of "gender balancing" over the last few decades for both groups. Theoretically speaking, and this comes from basic innate gender characteristics, male and female thought processes could be somewhat divergent. This is not to say that there is an abundance of testosterone in the cockpit or that females may be influenced by their inherent affective nature, but the gender differences do have to be considered when groups are segregated into mostly male versus mostly female categories.

Besides gender influences, the most salient reason for division in these groups appears to lie in the division of job functions and responsibilities. The cockpit crew is separated from the cabin crew by not only physical barriers (the door), but also communicative barriers (most communication is conducted through an impersonal interphone). Until relatively recently, pilots considered the cockpit "their territory" while the Cabin crew considered the cabin "their territory." Typically, the only times that these two groups would interface was when the pilots needed to be fed, or in the event of an emergency.

"the basic problem is that these two crews represent two distinct and separate cultures, and that this separation serves to inhibit satisfactory teamwork."

Well, we have - the pilots and the Cabin crew have respect amongst one another as friends but when it comes to working as a crew, we don't work as a crew. We work as two crews. You have a front-end crew and a back-end crew, and we are looked upon as serving coffee and lunch and things like that.

By now you have seen the magnitude of the problem; two groups, two cultures, and two completely separate job functions. The pilots, who work in the small but highly complex cockpit—and the Cabin crew, who come from the service-oriented and spacious cabin—having difficulties bringing their environments closer together and working in harmony.

Pilots and Cabin crew need to understand the basic psychology of group dynamics and the positive effect that pre-flight briefings can have between groups. Many pilots and Cabin crew may have never worked together before and yet both of these groups tend to remain isolated before, during, and after a flight. Some captains are better with an introduction and a briefing than others. But overall, there tends to be a "chill in the air" during pre-flight routines.

RUNWAY INCURSION

A runway incursion is an incident where an unauthorized aircraft, vehicle or person is on a runway. This adversely affects runway safety, as it creates the risk that an airplane taking off or landing will collide with the object.  It is defined by ICAO as Any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle, or person on the protected area of a surface designated for the landing and take-off of aircraft.

A major disaster was averted at the CSI Airport , Mumbai last year after an aircraft, which was supposed to be on the taxiway, entered the runway area, while another had been cleared to land.

These close calls between aircraft and other planes, ground vehicles and hazards have grown steadily over the years and are now a grave concern for safety officials across the world.

An effective Runway incursion prevention program should be capable of

·         Alerting the pilots to conflicting traffic in the air and on the runways, taxiways and ramps;

·         Allowing more aircraft to land safely on time in bad weather

·         Improving communication between pilots and air traffic controllers ; and

·         Virtually eliminating the world’s greatest cause of aviation fatalities – controlled flight into terrain or CFIT.

Please offer your comments experiences and suggestions.