During the process of developing a team, absence and vacation time should be discussed with each employee. If they are unable to be present enough to get the project done by the deadline, the team member should be replaced accordingly. If a member has a family emergency that is out of their control, the work should be distributed or a temporary employee should be hired that can do the work.

All of the responsibility designation and time allotment should be discussed and distributed during the planning phase. With proper communication no ones vacation plans should be a surprise. However, there are personal problems that come up. If the teams vacations are discussed during planning then there work will be completed before they leave or after they come back, depending on when their task deadline is. If they will not be able to complete their task when it is needed then they should bow out and have someone else take their place.
When they are in the execution phase and something unforeseen comes up then depending on how long their absence will be they can work from home, be replaced, or split their work among other team members until they return. With proper planning their should not be an issue during execution when it comes to team member absence.

If you're in the Executing Phase it is the Project Manager's responsibility to make sure that the team is performing their tasks on schedule and to deal with a team member's vacation, or absence. As @cdj24 mentions, it should be communicated in the planning phase if a team member is planning to take a big vacation or be absent from work. However, I believe that if the team member decides after the Planning phase to take a vacation, that he/she would require approval from the project manager. In my office we have "Time Away forms" where we select what we are requesting time taken "Vacation, Scheduled Sick day (doctor appointment), Bereavement, etc" and then our manager has to sign off and the office admin puts the information in the "Time Away Calendar" that everyone in the office has access to. This I think would be the best process because in this situation the Project Manager can see if it would be appropriate with the Project timeline if that team member can take off or if they are required to meet certain deliverables. There will definitely be situations where the will be a family emergency or personal problem and the Project Manager will have to see as @cdj24 mentions if they can work remotely, be replaced, or have someone cover their responsibilities while they are out. Overall, I don't think there should be too many surprises with team members taking vacation or taking time off, but there should be a company process so that there is a clear dialog with the team members and manager so the project can meet its milestones and timeline for deliverables is adhered to. Everyone knows people will take vacation, get sick, have a family emergency so this should be accounted for in the planning stage and a process implemented for when these occur.

Typically the Project Manager would be notified ahead of time if it's for a personal leave. If its an unexpected leave, then the PM would need to accommodate and move dates and action items around to the remaining members of the team to meet deadlines. Now what this does is create more work for everyone. Good communication is essential in all aspects especially when a team is down a member. Instead of being in charge of one action item, a member of the team may receive another item or share one with another teammate which is a good idea given that it's not all charged on one person. However, this isn't always the case.

In such cases project manager can talk to the department head and ask for a other person from that department to get to Know about the project and get started in place of the person who had his issue. This things are really out of hand where you can ask your employees to give a notice before going away from work for any sudden personal problem or any if he gets ill. So if you have matrix structured organisation you can do this. Project manager can later have meeting with this new guy and let him know the status of current project and show him from where he has to start.But if employee is out or sick only for few days than that delay is usually avoided by PM just by having that time buffer after making WBS while making the timeline.

From my past experience, When a PM starts a team development, they make sure they have backup more most of the members or at least for the critical ones. As a team when we accept a project we own it and everyone tried as best as the can to hit the target on time or even sometime before to leave a buffer time for unexpected. But of course, it doesn't work that way every time as emergencies happen. PM is always host meeting and document everything and that helps to be able to replace that member and update him with all the parts they need to know about it. My worst experience was when our CEO changed without any notice, all the members were frustrated as there was no clear direction from top mangement.

The work that the team would have to do should be design with contingencies in the event of a member suddenly not being present. Some of the things I have seen in y experience is have very open dialog in team meeting about scheduling the work in advance. That way it can be adjusted if anyone have a vacation that they would like to plan. In the event of sudden emergencies, where a teammate is suddenly absent and their work need to be don’t in a timely manner; the other member would have to member will have to split the work. The point of having a good team is to be able to cover each other back when the team should work as one large system made up of individual parts.

In my project team, we have a tab on our project dashboard with the vacation schedules and proxies of every single member of the team. This allows everyone to be aware of any planned vacations ahead of time, and who is taking over the responsibilities of the absent member while they are away. We have found this to be an effective way to keep the project moving.

A significant mistake in project planning is to assume full availability of all the team members. The management has the right to rearrange the employee vacation schedule to meet the deadlines. in the absence of a team member the project should not suffer so the PM should discuss with team members the plan in advance to avoid the conflicts and confusion during period of absence. The absent team member should inform their backups about the deliverable deadlines, key contracts summary of work in progress, major responsibilities ,access to important files and documents. The employee on vacation should inform his team member about best way to contract when on vacation if needed. Remind the employee about replying the office emails and voicemail in case of absence .Pm should also have part time employee backup when help is needed. He can also offer the employee to work from home and holiday pay. Vacation schedule should not be a hidden document so the team member can plan vacation around their colleagues schedule.

After the team selection the project timeline is decided as a pert chart or gantt chart. Since the timeline is based on the days needed to work on every single tasks of the whole project a gantt chart can useful. The days of vacation or holidays can be fixed in the timeline and there should be an early start to aim for early finish. Even if there are unlisted leave of the work day,There will be more chances to finish the project early or on time if the start is early in the decided timeline

I think that the planning process should be done in a way where vacation and certain absences from employees will not derail the timeline. What I am saying is that there should be some cushion for employees to be absent, even unplanned absences. For example, for an employee with children it should be taken into consideration that kids get sick. Let say about 3 times a year. So for that employee maybe it should be calculated that in a year long project, he/she might have an unplanned absence 3 times. He/she might be absent less times, which is great, or more times. Of course, theres certain scenarios that can not be planned for such as a very severe accident. I am not sure if doing schedules like this would be an HR problem. But, I just think tailoring timelines this way would result in more accurate timelines.

The project manager should discuss the amount of work and timeframe required for the project with potential members to make sure they can fully commit to the project. That timeframe should include vacation days, and additional days for unexpected emergencies. After the team is formed, members will need to log in their expected absences on a communal calendar at least a week in advance. Around five to seven extra days should cover emergencies for all of the team members. Also, if a member uses up too many emergency absences, the PM may need to cut into or delay their vacation time to keep everything on schedule.
If possible, the PM can hire one or two extra part-timers who will be kept up to date by attending design review meetings. They can then fill in whenever too many full-time members are absent.

The planning phase takes place before the execution phase. In this phase the project timeline is set with the help of the gantt chart. Here all the timelines for the tasks are set taking into consideration most of the factors that would have affected the project timeline in any manner. Also any sort of pre-planned vacation of any of the team member must be discussed with the PM during the meeting held usually after the team selection so that workarounds are planned in advance such as hiring a temporary candidate to follow-up with the task. Apart from this depending on the length of the project three to five days of leaves should be should be accounted for during the planning phase if any sort of emergencies come up during the project.

Well there's a few factors that affect this. What level employee are you? Managers may have a harder time taking off if they cannot get the appropriate person to hold the reins while they're away. A lower "grunt" may have an easier time if their work is easy for others to assist with. Personal time is usually always approved weeks if not months in advance. Emergency days such as a dying family member is always allowed, and of course you can't plan for these in advance. A robust system is the best way to deal with these issues. Having people who can take over for the employee is critical. There's a lot of factors that go into this, such as type of project, amount of workers, etc. but a strong capable team is the best way to deal with this issue.